139 results on '"Alberto Navalón"'
Search Results
2. Analysis of polycyclic-aromatic hydrocarbons in blood serum samples obtained from oil refinery workers. Determination of occupational exposure
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Morsina Çipa, María del Carmen Gómez-Regalado, Alberto Navalón, Elda Marku, and Alberto Zafra-Gómez
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Atmospheric Science ,Pollution ,Waste Management and Disposal - Published
- 2022
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Catalog
3. Determination of Vecuronium Bromide in Pharmaceuticals: Development, Validation and Comparative Study of HPLC and CZE Analytical Methods
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García, Pedro López, Gomes, Fabio Pereira, Santoro, Maria Inês Rocha Miritello, Kedor-Hackmann, Érika Rosa Maria, Quero, Jose Luis Vilchez, Montón, Alberto Navalón, Montoya, Guillermo Crovetto, and Cabrera, Mercedes Aguilera more...
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- 2011
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4. Determination of ultraviolet filters in human nails using an acid sample digestion followed by ultra-high performance liquid chromatography-mass spectrometry analysis
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Alberto Navalón, Laura Martín-Pozo, María del Carmen Gómez-Regalado, Alberto Zafra-Gómez, and Samuel Cantarero-Malagón
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Male ,Analyte ,Environmental Engineering ,Swine ,Health, Toxicology and Mutagenesis ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,Mass spectrometry ,01 natural sciences ,Matrix (chemical analysis) ,Liquid chromatography–mass spectrometry ,Tandem Mass Spectrometry ,medicine ,Environmental Chemistry ,Animals ,Humans ,Chromatography, High Pressure Liquid ,0105 earth and related environmental sciences ,Detection limit ,Chromatography ,Chemistry ,Selected reaction monitoring ,Extraction (chemistry) ,Public Health, Environmental and Occupational Health ,General Medicine ,General Chemistry ,Pollution ,020801 environmental engineering ,medicine.anatomical_structure ,Nails ,Nail (anatomy) ,Digestion ,Female ,Sunscreening Agents - Abstract
Ultraviolet filters (UV-filters) are specific chemicals that absorb and reflect UVA and UVB radiation from the sun. They are regularly used in sunscreens and in other personal care products (PCPs), and in products like plastics, adhesives, toys, or furniture finishes. This work develops and validates a new method to determine concentrations of UV-filters (BP-1, BP-2, BP-3, BP-6, BP-8, 4-OH-BP, THB, AVB) in human nail samples. Nails are easily available and are considered to be suitable indicators of cumulative and continued exposure to harmful chemicals. The treatment of nail samples includes microwave assisted digestion/extraction (MAE) in a methanolic solution of o-phosphoric acid (0.05 mol L−1) followed by analyte determination using ultra-high performance liquid chromatography–mass spectrometry (UHPLC–MS/MS) in multiple reaction monitoring mode. The analytes were separated in less than 10 min. The digestion procedure was optimized using multivariate techniques. Matrix-matched calibration with a pig hoof matrix was used for validating the method. A study of accuracy with spiked blank samples was also conducted. The calculated detection limits varied between 0.2 and 1.5 ng g−1, and quantification limits between 1.0 and 5.0 ng g−1. The trueness of the method was an estimation of the recovery, which was between 90.2% and 112.2%; with an estimated precision (relative standard deviation, % RSD) lower than 12.3% for all UV-filters. Nail samples were obtained from 22 volunteers (male and female). The results showed that BP-1 and BP-3 mainly bioaccumulate in human nails. more...
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- 2020
5. Assessment of parabens and ultraviolet filters in human placenta tissue by ultrasound-assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry
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N. Olea, M.E. Gallardo-Torres, José Ramón Ortega Pérez, Alberto Navalón, Mariana F. Fernández, F. Vela-Soria, Oscar Ballesteros, and Caridad Díaz
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Placenta ,media_common.quotation_subject ,Relative standard deviation ,Parabens ,Endocrine Disruptors ,010501 environmental sciences ,Mass spectrometry ,Ultrasound assisted ,01 natural sciences ,Biochemistry ,Cosmetics ,Chemistry Techniques, Analytical ,Analytical Chemistry ,Limit of Detection ,Pregnancy ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Humans ,Ultrasonics ,Chromatography, High Pressure Liquid ,0105 earth and related environmental sciences ,media_common ,Chromatography ,Chemistry ,010401 analytical chemistry ,Organic Chemistry ,Extraction (chemistry) ,Reproducibility of Results ,Human placenta ,General Medicine ,0104 chemical sciences ,Female ,Ultra high performance - Abstract
Increasing concerns have been raised over recent decades about human exposure to Endocrine Disrupting Chemicals (EDCs), especially about their possible effects on embryo, foetus, newborn, and child. Parabens (PBs) and ultraviolet filters (UV-filters) are prevalent EDCs widely used as additives in cosmetics and personal care products (PCPs). The objective of this study was to determine the presence of four PBs and ten UV-filters in placental tissue samples using a novel analytical method based on ultrasound-assisted extraction (UAE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC–MS/MS). Multivariate optimization strategies were used to accurately optimize extraction and clean-up parameters. Limits of quantification ranged from 0.15 to 0.5 μg kg−1, and inter-day variability (evaluated as relative standard deviation) ranged from 3.6% to 14%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery percents ranged from 94.5% to 112%. The method was satisfactorily applied for the determination of the target compounds in human placental tissue samples collected at delivery from 15 randomly selected women. This new analytical procedure can provide information on foetal exposure to compounds, which has been little studied. more...
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- 2017
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6. Validated method for the determination of perfluorinated compounds in placental tissue samples based on a simple extraction procedure followed by ultra-high performance liquid chromatography–tandem mass spectrometry analysis
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Julia Martín, Alberto Navalón, José Luis Vilchez, R. Rodríguez-Gómez, Alberto Zafra-Gómez, and Esteban Alonso
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Quality Control ,Time Factors ,Placenta ,Chemical Fractionation ,010501 environmental sciences ,Tandem mass spectrometry ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Limit of Detection ,Pregnancy ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Humans ,Chromatography, High Pressure Liquid ,0105 earth and related environmental sciences ,Detection limit ,Fluorocarbons ,Chromatography ,010401 analytical chemistry ,Extraction (chemistry) ,Temperature ,Contamination ,0104 chemical sciences ,Perfluorooctane ,Freeze Drying ,chemistry ,Bioaccumulation ,Linear Models ,Solvents ,Environmental Pollutants ,Female - Abstract
Xenobiotic exposure during pregnancy is inevitable. Determination of perfluorinated compounds (PFCs), chemicals described as environmental contaminants by Public Health Authorities due to their persistence, bioaccumulation and toxicity, is a challenge. In the present work, a method based on a simplified sample treatment involving freeze-drying, solvent extraction and dispersive clean-up of the extracts using C18 sorbents followed by an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis was developed and validated for the determination of five perfluorinated carboxylic acids (C4-C8) and perfluorooctane sulfonate (PFOS) in placental tissue samples. The most influential parameters affecting the extraction method and clean-up were optimized using Design of Experiments (DOE). The method was validated using matrix-matched calibration. Found limits of detection (LODs) ranged from 0.03 to 2 ng g(-1) and limits of quantification (LOQs) from 0.08 to 6 ng g(-1), while inter- and intra-day variability was under 14% in all cases. Recovery rates for spiked samples ranged from 94% to 113%. The method was satisfactorily applied for the determination of compounds in human placental tissue samples collected at delivery from 25 randomly selected women. more...
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- 2016
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7. Simultaneous determination of quinolone and β-lactam residues in raw cow milk samples using ultrasound-assisted extraction and dispersive-SPE prior to UHPLC−MS/MS analysis
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Alberto Navalón, Dolores Barrón, Alexandra Junza, Alberto Zafra-Gómez, and N. Dorival-García
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Sorbent ,Chromatography ,Chemistry ,medicine.drug_class ,010401 analytical chemistry ,Extraction (chemistry) ,04 agricultural and veterinary sciences ,Buffer solution ,Quinolone ,040401 food science ,01 natural sciences ,0104 chemical sciences ,Solvent ,chemistry.chemical_compound ,0404 agricultural biotechnology ,medicine ,media_common.cataloged_instance ,Methanol ,European union ,Food Science ,Biotechnology ,media_common ,Piperacillin ,medicine.drug - Abstract
A new sensitive, selective and accurate method to determine 17 quinolone and 14 β-lactam antibiotic residues in raw cow milk samples has been validated. The method is based on the extraction of the antibiotics by ultrasound-assisted extraction (UAE) followed by a clean-up step using a dispersive solid-phase extraction (d-SPE) sorbent. Experimental designs have been used for extraction and clean-up optimization. The extraction solvent selected was a mixture of acetonitrile/methanol/McIlvaine buffer solution (60:25:15; v/v/v) at pH 6. A volume of 15 mL of this extraction solvent was added to freeze-dried milk samples and the mixtures were sonicated during 20 min at 70% amplitude. The extracts were further cleaned-up with PSA (primary-secondary amine) sorbent and analysed by UHPLC-ESI(+)-MS/MS. Cincophen and piperacillin were used as surrogates for quinolones and β-lactams, respectively. The method was validated according to European Directive 2002/657/EC and FDA guideline. Recovery rates ranged from 96.0% to 104.5%. The limits of quantification of the method ranged from 0.3 to 2.0 ng g−1, while inter- and intra-day variability was under 7.1% in all cases. The method was applied to the determination of selected antibiotics in 28 raw cow milk samples. A percentage of 28% of the samples were positive in any of the studied antibiotics, however, only 11% were considered non-compliant with the current European Union legislation (Commission Regulation 37/2010). more...
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- 2016
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8. Determination of endocrine disrupting chemicals in human nails using an alkaline digestion prior to ultra-high performance liquid chromatography–tandem mass spectrometry
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Laura Martín-Pozo, Alberto Zafra-Gómez, Alberto Navalón, Felix Hidalgo, and Samuel Cantarero-Malagón
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Adult ,Male ,Relative standard deviation ,Parabens ,02 engineering and technology ,Endocrine Disruptors ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Digestion (alchemy) ,Phenols ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Biomonitoring ,Humans ,Benzhydryl Compounds ,Child ,Chromatography, High Pressure Liquid ,Detection limit ,Fluorocarbons ,Chromatography ,Chemistry ,010401 analytical chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Nails ,Sodium hydroxide ,Female ,Ultra high performance ,0210 nano-technology ,Carbanilides ,Biological Monitoring - Abstract
Rapid industrialization has resulted in a progressive increase in human exposure to hazardous chemicals. The present work develops and validates a new method to determinate 18 endocrine disrupting chemicals (EDCs) in human nail samples. In contrast to other common biological samples, nail sampling is non-invasive and since they take several months to grow out, they are well suited for measuring and reflecting the cumulative exposure to harmful substances in the long term. A digestion of samples with a 0.04 M solution of sodium hydroxide is carried out followed by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS), working in multiple-reaction-monitoring (MRM) mode. The compounds were separated in 8 min. Multivariate optimization strategies were used for the optimization of the parameters that affects the digestion procedure. The validation was developed using a matrix-matched calibration and a recovery assay with spiked samples. The limits of detection and quantification ranged from 0.3 to 1.2 ng g−1 and from 1 to 5 ng g−1, respectively. Recovery rates for spiked samples were between 88% and 113% and the relative standard deviation (% RSD) was lower than 12.7% for all studied EDCs. The method was applied for the analysis of these compounds in human nail samples from volunteers. All samples tested positive for several of the analyzed EDCs. more...
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- 2020
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9. Analysis of 17 neurotransmitters, metabolites and precursors in zebrafish through the life cycle using ultrahigh performance liquid chromatography–tandem mass spectrometry
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E. Vazquez, Alberto Zafra-Gómez, A. Santos-Fandila, Ricardo Rueda, Maria Ramirez, Alberto Navalón, and A. Barranco
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Detection limit ,Life Cycle Stages ,Neurotransmitter Agents ,Analyte ,Chromatography ,Chemistry ,Formic acid ,Electrospray ionization ,Clinical Biochemistry ,Cell Biology ,General Medicine ,Tandem mass spectrometry ,Mass spectrometry ,Biochemistry ,Analytical Chemistry ,Triple quadrupole mass spectrometer ,chemistry.chemical_compound ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Animals ,Chromatography, High Pressure Liquid ,Zebrafish - Abstract
An ultrahigh performance liquid chromatography-tandem mass spectrometry method for the identification and quantification of neurotransmitters, metabolites and precursors at different stages in zebrafish life was developed. Betaine, glutamine, glutamic acid, γ-aminobutyric acid, phosphocholine, glycerophosphocholine, cytidine 5'-diphosphocholine, choline, acetylcholine, dopamine, norepinephrine, serotonin, tyrosine, epinephrine, tryptophan, 5-hydroxyindolacetic acid and agmatine were selected as analytes. The method consisted of a simple deproteinization of samples using methanol and formic acid, subsequent injection onto the chromatographic equipment and quantification with a triple quadrupole mass spectrometer detector using an electrospray ionization interface in positive mode. Limits of detection ranged from 0.02 to 11ngmL(-1) and limits of quantification from 0.1 to 38ngmL(-1), depending on the analyte. The method was validated according to US Food and Drugs Administration (FDA) guideline for bioanalytical assays. Precision, expressed as relative standard deviation (%RSD), was lower than 15% in all cases, and the determination coefficient (R(2)) was equal or higher than 99.0% with a residual deviation for each calibration point lower than ±25%. Mean recoveries were between 85% and 115%. The method was applied to determine of these compounds in zebrafish from early stages of development to adulthood and showed the time-course of neurotransmitters and others neurocompounds through the life cycle. The possibility of measuring up to 17 compounds related with the main neurotransmitter systems in a simple analytical method will complement and reinforce the use of zebrafish in multiple applications in the field of neurosciences. The proposed method will facilitate future studies related with brain development. more...
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- 2015
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10. Analytical methods for the assessment of endocrine disrupting chemical exposure during human fetal and lactation stages: A review
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Alberto Zafra-Gómez, Alberto Navalón, I. Jiménez-Díaz, F. Vela-Soria, R. Rodríguez-Gómez, and Oscar Ballesteros
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Analyte ,Liquid Phase Microextraction ,Phthalic Acids ,Parabens ,Endocrine Disruptors ,Tandem mass spectrometry ,Biochemistry ,Specimen Handling ,Analytical Chemistry ,Molecular Imprinting ,Matrix (chemical analysis) ,Phenols ,Humans ,Environmental Chemistry ,Sample preparation ,Solid phase extraction ,Benzhydryl Compounds ,Spectroscopy ,Chromatography ,Milk, Human ,Chemistry ,Solid Phase Extraction ,Extraction (chemistry) ,Environmental chemistry ,Human fetal ,Female ,Gas chromatography ,Sunscreening Agents - Abstract
In the present work, a review of the analytical methods developed in the last 15 years for the determination of endocrine disrupting chemicals (EDCs) in human samples related with children, including placenta, cord blood, amniotic fluid, maternal blood, maternal urine and breast milk, is proposed. Children are highly vulnerable to toxic chemicals in the environment. Among these environmental contaminants to which children are at risk of exposure are EDCs -substances able to alter the normal hormone function of wildlife and humans-. The work focuses mainly on sample preparation and instrumental techniques used for the detection and quantification of the analytes. The sample preparation techniques include, not only liquid-liquid extraction (LLE) and solid-phase extraction (SPE), but also modern microextraction techniques such as extraction with molecular imprinted polymers (MIPs), stir-bar sorptive extraction (SBSE), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), matrix solid phase dispersion (MSPD) or ultrasound-assisted extraction (UAE), which are becoming alternatives in the analysis of human samples. Most studies focus on minimizing the number of steps and using the lowest solvent amounts in the sample treatment. The usual instrumental techniques employed include liquid chromatography (LC), gas chromatography (GC) mainly coupled to tandem mass spectrometry. Multiresidue methods are being developed for the determination of several families of EDCs with one extraction step and limited sample preparation. more...
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- 2015
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11. Determination of quinolone residues in raw cow milk. Application of polar stir-bars and ultra-high performance liquid chromatography-tandem mass spectrometry
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Alberto Navalón, Morsina Çipa, María Teresa García-Corcoles, Dolores Barrón, R. Rodríguez-Gómez, and Alberto Zafra-Gómez
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Nalidixic acid ,Health, Toxicology and Mutagenesis ,Food Contamination ,Quinolones ,Toxicology ,01 natural sciences ,chemistry.chemical_compound ,Sarafloxacin ,Liquid chromatography–mass spectrometry ,Tandem Mass Spectrometry ,PEG ratio ,medicine ,Animals ,Chromatography, High Pressure Liquid ,Chromatography ,Polydimethylsiloxane ,010405 organic chemistry ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,Solid Phase Extraction ,technology, industry, and agriculture ,Public Health, Environmental and Occupational Health ,General Chemistry ,General Medicine ,Piromidic acid ,Drug Residues ,0104 chemical sciences ,Milk ,Flumequine ,Cattle ,Food Science ,medicine.drug - Abstract
Seventeen quinolone antibiotics were determined in cows’ milk. A method of high sensitivity, selectivity and accuracy was developed. Accuracy (trueness and precision), linearity, sensitivity, selectivity, decision limit and detection capability were established following the recommendations of the Commission Decision 2002/657/EC and the Food and Drug Administration (FDA) guideline. The use of polar stir-bar sorptive extraction (SBSE) prior to UHPLC-MS/MS analysis is proposed. The variables that affect SBSE were optimised using multivariate optimisation strategies. The ionic strength, the extraction time and the sample volume were studied. pH and stir-bar coating (polydimethylsiloxane, PDMS, and polyethyleneglycol modified silicone, PEG) were studied. PEG showed the best extraction yield at pH 6. For validation, a matrix-matched calibration and a recovery assay were carried out. Limits of quantification from 0.5 μg kg−1 for nalidixic acid, flumequine and piromidic acid, to 4.0 μg kg−1 for sarafloxacin were calculated. The precision (%, RSD) was lower than 15% for all antibiotics. Recoveries in fortified samples were between 88 and 114%. more...
- Published
- 2018
12. Matrix solid phase dispersion for the extraction of selected endocrine disrupting chemicals from human placental tissue prior to UHPLC-MS/MS analysis
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Alberto Navalón, Oscar Ballesteros, Alberto Zafra-Gómez, F.J. Camino-Sánchez, L. Ballesteros, and F. Vela-Soria
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Butylparaben ,education.field_of_study ,Bisphenol A ,Chromatography ,Population ,Extraction (chemistry) ,Mass spectrometry ,Analytical Chemistry ,Matrix (chemical analysis) ,chemistry.chemical_compound ,chemistry ,Analytical procedures ,Ethylparaben ,education ,Spectroscopy - Abstract
In recent decades, in parallel to industrial development, a large amount of new chemicals have emerged that are able to produce disorders in the human endocrine system. These groups of substances, so-called endocrine disrupting chemicals (EDCs), include many families of compounds, such as parabens, benzophenones and bisphenols. Given the demonstrated biological activity of those compounds, it is necessary to develop new analytical procedures to evaluate the exposure with the final objective of establishing, in an accurate way, relationships between EDC concentrations and the harmful health effects observed in the population. In the present study, a method based on a sample treatment by matrix solid phase dispersion (MSPD) for the extraction of four parabens (methyl-, ethyl-, propyl- and butylparaben), five bisphenols (bisphenol A and monochloro-, dichloro-, trichloro- and tetrachlorobisphenol A) and benzophenone-3 in human placental tissue samples, followed by ultra high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) analysis is proposed. The extraction parameters were accurately optimized using multivariate optimization strategies. Ethylparaben ring- 13 C 6 , benzophenone-d 10 and bisphenol A-d 16 were used as surrogates. The found limits of quantification (LOQ) ranged from 0.2 to 0.4 ng g − 1 and the precision, evaluated as relative standard deviation, ranged from 6.1% to 14.8%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery rates from 96% to 105% were obtained. The method was satisfactorily applied for the determination of target compounds in human placenta samples from 10 randomly selected women. more...
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- 2015
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13. Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples
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Lilia Araujo, Avismelsi Prieto, Paola Valera, Maria Betzabeth Espina-Benitez, Ana Zambrano, Vincent Dugas, Alberto Navalón, Jose Luis Vilchez, Separative Methods - Techniques séparatives, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Lab Analyt Chem & Electrochem, Universidad del Zulia (LUZ), Analytical Chemistry, and University of Granada [Granada] more...
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Sorbent ,Capillary zone electrophoresis ,Health, Toxicology and Mutagenesis ,Stacking ,lcsh:Medicine ,Porapak Q ,acidic drugs ,capillary zone electrophoresis ,solid-phase microextraction ,porapak Q ,010402 general chemistry ,Solid-phase microextraction ,01 natural sciences ,Article ,Clofibric Acid ,Capillary electrophoresis ,Naproxen ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Fiber ,Solid Phase Microextraction ,Detection limit ,Chromatography ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,lcsh:R ,Public Health, Environmental and Occupational Health ,Fractional factorial design ,Electrophoresis, Capillary ,Acid drugs ,6. Clean water ,0104 chemical sciences ,Ketoprofen ,[SDE]Environmental Sciences ,Water Pollutants, Chemical - Abstract
A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L−1 and 2.91 and 3.86 µg∙L−1, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers., The Council of Scientific and Humanistic Development (abbreviated as CONDES in Spanish). The University Sector Planning Office (abbreviated as OPSU in Spanish) and the Research Division of the Engineering Faculty. more...
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- 2017
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14. Seasonal Variations in the Behavior of Alcohol Sulfates in Agricultural Soils: a Field Study
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Miguel Perez-Pascual, C. Fernández-Ramos, Juan A. de Ferrer, Alberto Zafra-Gómez, Dalibor Šatínský, C. Verge, Peter Solich, Oscar Ballesteros, Alberto Navalón, and José Luis Vilchez
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Irrigation ,Environmental Engineering ,Ecological Modeling ,010401 analytical chemistry ,Environmental engineering ,Amendment ,010501 environmental sciences ,01 natural sciences ,Pollution ,Reclaimed water ,0104 chemical sciences ,Wastewater ,Groundwater pollution ,Soil water ,Environmental Chemistry ,Environmental science ,Leaching (agriculture) ,Surface runoff ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Irrigation with reclaimed water and soil amendment with sewage sludge are becoming common practices in arid and semiarid areas. When wastewater treatments do not efficiently remove all the contaminants, these contaminants can later end up in agricultural soils. These contaminated soils are a potential source of surface and groundwater pollution by leaching and runoff. In the present work, we assessed the behavior of alcohol sulfates (AS) in agricultural soil. For the experimental work, a tract of soil was irrigated with linear alcohol sulfates with 12–18 hydrocarbon chain and subsequently tested for AS concentration from November 2014 to July 2015. The highest concentrations of AS were found at the top layer of soil (29.80 to 6.23 mg kg−1). The adsorption rate and the amount of surfactant adsorbed increased as the length of the hydrocarbon chain increases. AS homologues can leach up to 60 cm. A mathematical model was applied to predict the environmental behavior of AS in the agricultural soils studied. Disappearance rate constant (k) values for AS homologues were between −5.10·10−3 and −1.68·10−2 h−1, and average half-life values were between 37 and 135 h. Coefficients of determination (R 2) between 92.4 and 99.1% showed that the proposed model satisfactorily describes the experimental results. The present study provides a conceptual framework and essential parameters for predicting and understanding the environmental behavior of AS in agricultural soils. more...
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- 2017
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15. A multiresidue method for the determination of selected endocrine disrupting chemicals in human breast milk based on a simple extraction procedure
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Oscar Ballesteros, I. Jiménez-Díaz, R. Rodríguez-Gómez, Alberto Zafra-Gómez, and Alberto Navalón
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Butylparaben ,education.field_of_study ,Bioanalysis ,Bisphenol A ,Chromatography ,Milk, Human ,Population ,Extraction (chemistry) ,Endocrine Disruptors ,Mass spectrometry ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Limit of Detection ,Tandem Mass Spectrometry ,Calibration ,Humans ,Endocrine system ,Female ,Analytical procedures ,education ,Chromatography, High Pressure Liquid - Abstract
In recent decades, in parallel to industrial development, a large amount of new chemicals have emerged that are able to produce disorders in human endocrine system. These groups of substances, so-called endocrine disrupting chemicals (EDCs), include many families of compounds, such as parabens, benzophenone-UV filters and bisphenols. Given the demonstrated biological activity of those compounds, it is necessary to develop new analytical procedures to evaluate the exposure with the final objective of establishing, in an accurate way, relationships between EDCs concentrations and the harmful health effects observed in population. In the present work, a method based on a simplified sample treatment involving steps of precipitation, evaporation and clean-up of the extracts with C18 followed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis for the determination of bisphenol A and its chlorinated derivatives (monochloro-, dichloro-, trichloro- and tetrachlorobisphenol A), parabens (methyl-, ethyl-, propyl- and butylparaben) and benzophenone-UV filters (benzophenone -1,-2, -3, -6, -8 and 4-hydroxybenzophenone) in human breast milk samples is proposed and validated. The limits of detections found ranged from 0.02 to 0.05 ng mL(-1). The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery rates ranged from 91% to 110% and the precision (evaluated as relative standard deviation) was lower than 15% for all compounds, being within the acceptable limits for the selected bioanalytical method validation guide. The method was satisfactorily applied for the determination of these compounds in human breast milk samples collected from 10 randomly selected women. more...
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- 2014
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16. Analytical methods for the determination of personal care products in human samples: An overview
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Oscar Ballesteros, Alberto Navalón, Alberto Zafra-Gómez, and I. Jiménez-Díaz
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Male ,Serum ,Ultraviolet Rays ,Sample (material) ,Human life ,Liquid-Liquid Extraction ,Endocrine Disruptors ,Urinalysis ,Analytical Chemistry ,Benzophenones ,Semen ,Adverse health effect ,Humans ,Sample preparation ,Organic Chemicals ,Volume concentration ,Personal care ,Milk, Human ,Chemistry ,Organic chemicals ,Preservatives, Pharmaceutical ,Solid Phase Extraction ,Body Fluids ,Perfume ,Environmental chemistry ,Anti-Infective Agents, Local ,Female ,Biochemical engineering ,Sunscreening Agents ,Disinfectants - Abstract
Personal care products (PCPs) are organic chemicals widely used in everyday human life. Nowadays, preservatives, UV-filters, antimicrobials and musk fragrances are widely used PCPs. Different studies have shown that some of these compounds can cause adverse health effects, such as genotoxicity, which could even lead to mutagenic or carcinogenic effects, or estrogenicity because of their endocrine disruption activity. Due to the absence of official monitoring protocols, there is an increasing demand of analytical methods that allow the determination of those compounds in human samples in order to obtain more information regarding their behavior and fate in the human body. The complexity of the biological matrices and the low concentration levels of these compounds make necessary the use of advanced sample treatment procedures that afford both, sample clean-up, to remove potentially interfering matrix components, as well as the concentration of analytes. In the present work, a review of the more recent analytical methods published in the scientific literature for the determination of PCPs in human fluids and tissue samples, is presented. The work focused on sample preparation and the analytical techniques employed. more...
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- 2014
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17. Stir-membrane solid–liquid–liquid microextraction for the determination of parabens in human breast milk samples by ultra high performance liquid chromatography-tandem mass spectrometry
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Alberto Navalón, Miguel Valcárcel, Alberto Zafra-Gómez, M. Roldán-Pijuán, Rafael Lucena, R. Rodríguez-Gómez, Oscar Ballesteros, and Soledad Cárdenas
- Subjects
Detection limit ,Analyte ,Aqueous solution ,Chromatography ,Milk, Human ,Liquid Phase Microextraction ,Chemistry ,Organic Chemistry ,Analytical chemistry ,General Medicine ,Tandem mass spectrometry ,Biochemistry ,Analytical Chemistry ,Triple quadrupole mass spectrometer ,Membrane ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Calibration ,Solvents ,Humans ,Solid phase extraction ,Chromatography, High Pressure Liquid ,Solid Phase Microextraction - Abstract
In this article, stir-membrane solid-liquid-liquid microextraction (SM-SLLME) is tailored for the analysis of solid matrices and it has been evaluated for the determination of parabens in l breast milk samples. A three-phase microextraction mode was used for the extraction of the target compounds taking advantage of their acid-base properties. The unit allows the simultaneous extraction of the target compounds from the solid sample to an organic media and the subsequent transference of the analytes to an aqueous acceptor phase. The method includes the identification and quantification of the analytes by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). All the variables involved in the extraction procedure have been accurately studied and optimized. The analytes were detected and quantified using a triple quadrupole mass spectrometer (QqQ). The selection of two specific fragmentation transitions for each compound allowed simultaneous quantification and identification. The method has been analytically characterized on the basis of its linearity, sensitivity and precision. Limits of detection ranged from 0.1 to 0.2ngmL(-1) with precision better than 8%, (expressed as relative standard deviation). Relative recoveries were in the range from 91 to 106% which demonstrated the applicability of the stir-membrane solid-liquid-liquid microextraction for the proposed analytical problem. Moreover, the method has been satisfactorily applied for the determination of parabens in lyophilized breast milk samples from 10 randomly selected individuals. more...
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- 2014
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18. UHPLC–MS/MS method for the determination of bisphenol A and its chlorinated derivatives, bisphenol S, parabens, and benzophenones in human urine samples
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Alberto Zafra-Gómez, F. Vela-Soria, L. Ballesteros, Alberto Navalón, and Oscar Ballesteros
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Male ,Bisphenol A ,Liquid Phase Microextraction ,Bisphenol ,Parabens ,Urinalysis ,Tandem mass spectrometry ,Biochemistry ,Analytical Chemistry ,Benzophenones ,chemistry.chemical_compound ,Phenols ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Humans ,Benzhydryl Compounds ,Ethylparaben ,Chromatography, High Pressure Liquid ,Butylparaben ,Chromatography ,Extraction (chemistry) ,Reproducibility of Results ,Hydrogen-Ion Concentration ,chemistry ,Bisphenol S ,Solvents ,Female ,Salts ,Chlorine ,Chromatography, Liquid - Abstract
In the present work, a new method based on a sample treatment by dispersive liquid-liquid microextraction (DLLME) for the extraction of six bisphenols (bisphenol A, bisphenol S, and monochloro-, dichloro-, trichloro-, and tetrachlorobisphenol A), four parabens (methyl-, ethyl-, propyl-, and butylparaben), and six benzophenones (benzophenone-1, benzophenone-2, benzophenone-3, benzophenone-6, benzophenone-8, and 4-hydroxybenzophenone) in human urine samples, followed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, is validated. An enzymatic treatment allows determining the total content of the target EDCs. The extraction parameters were accurately optimized using multivariate optimization strategies. Ethylparaben ring-(13)C6, benzophenone-d10, and bisphenol A-d16 were used as surrogates. Limits of quantification ranging from 0.1 to 0.6 ng mL(-1) and interday variabilities (evaluated as relative standard deviations) from 2.0 to 13.8% were obtained. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery rates ranged from 94 to 106%. A good linearity, for concentrations up to 300 ng mL(-1) for parabens and 40 ng mL(-1) for benzophenones and bisphenols, was also obtained. The method was satisfactorily applied for the determination of target compounds in human urine samples from 20 randomly selected individuals. more...
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- 2014
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19. A new method for the determination of benzophenone-UV filters in human serum samples by dispersive liquid–liquid microextraction with liquid chromatography–tandem mass spectrometry
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F. Vela-Soria, Alberto Navalón, L. Ballesteros, Alberto Zafra-Gómez, and Oscar Ballesteros
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Chromatography ,Liquid Phase Microextraction ,Ultraviolet Rays ,media_common.quotation_subject ,Extraction (chemistry) ,Reproducibility of Results ,medicine.disease_cause ,medicine.disease ,Cosmetics ,Analytical Chemistry ,Benzophenones ,chemistry.chemical_compound ,chemistry ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,medicine ,Benzophenone ,Humans ,media_common.cataloged_instance ,Irradiation ,European union ,Sunburn ,Ultraviolet ,Chromatography, Liquid ,media_common - Abstract
Benzophenone-UV filters (BP-UV filters) are extensively used in cosmetics products to avoid damaging effects of UV radiation. Despite their low toxicity, many research papers indicate that BP-UV filters are weak endocrine disruptors (EDCs). There are clear relationships between BP-UV filters exposure and several health disorders such as carcinogenesis and malformations observed in animals. In the present work, a new sample treatment procedure by dispersive liquid-liquid microextraction (DLLME) is proposed for the extraction of six BPs, namely benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), benzophenone-6 (BP-6), benzophenone-8 (BP-8) and 4-hydroxybenzophenone (4-OH-BP), in human serum samples, followed by ultra-high performance liquid chromatography-tandem mass spectro- metry (UPLC-MS/MS) analysis. The method involves an enzymatic treatment to quantify the total content (free plus conjugated species) of BP-UV filters in serum. The extraction parameters were accurately optimized using multivariate optimization approach. Benzophenone-d10 (BP-d10) was used as surrogate. Limits of quantification (LOQs) ranged from 0.4 to 0.9 ng mL � 1 and inter-day precision (evaluated as relative standard deviation) ranged from 1.9% to 13.1%. The method was validated using matrix-matched calibration and a recovery assay. Recovery rates for spiked samples ranged from 97% to 106%, and acceptable linearity was obtained up to concentrations of 40 ng mL � 1 . The method was applied to the determination of the target compounds in human serum samples from 20 randomly selected anonymous individuals. Harmful health effects of UV radiation have been demonstrated many years ago. The increasing exposure to UV irradiation raises a growing demand for chemicals which protect the skin against sunburn, photoageing, skin cancer, and photodermatosis. These chemicals, commonly referred as ultraviolet (UV) filters, are able to absorb UV solar radiation and protect human skin from direct exposure. UV filters posses single or multiple aromatic structures, commonly conjugated with different chemicals groups (carbonyl, double bounds, etc.), that are able to absorb UV radiation photons. These compounds are used extensively in sunscreens, cosmetic products such as facial day creams, after-shave products, makeup formulations, lipsticks, shampoos, and in plastic based packaging materials. In the European Union, 26 different organic compounds are permitted for those uses. The maximum content of these more...
- Published
- 2014
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20. Sorption and desorption of alcohol sulfate surfactants in an agricultural soil
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Alberto Zafra-Gómez, Rafael A. García-Delgado, C. Fernández-Ramos, Sara Isabel Crovetto, Rosario Blanc-García, B. Oliver-Rodríguez, Oscar Ballesteros, Alberto Navalón, and José Luis Vilchez
- Subjects
chemistry.chemical_compound ,chemistry ,Kinetic model ,Health, Toxicology and Mutagenesis ,Desorption ,Environmental chemistry ,Kinetics ,Soil water ,Batch reactor ,Environmental Chemistry ,Sorption ,Alcohol ,Sulfate - Abstract
Alcohol sulfates are one of the most important types of commercial anionic surfactants and may pose serious environmental problems. The present study examines the sorption behavior of alcohol sulfates in an agricultural soil using a batch reactor and column experiments. Kinetics and equilibrium isotherms of the sorption and desorption processes of the following alcohol sulfate homologues have been determined: AS-C12, AS-C14, AS-C16, and AS-C18. Sorption and desorption occurred rapidly, and equilibrium was achieved in approximately 1 h. The sorbed mass percentages were 35.1% AS-C12, 67.2% AS-C14, and 100% for both AS-C16 and AS-C18. A pseudo–first-order kinetic model provided an adequate fit of data. Sorption and desorption equilibrium data were fitted into 1) a linear model, with r2 values in the ranges 0.712 to 0.988 and 0.736 to 0.983, respectively, and 2) a Freundlich model, with r2 values in the ranges 0.956 to 0.991 and 0.891 to 0.981, respectively. Continuous-flow experiments in soil columns were carried out to obtain the breakthrough curves for each compound. The present study provides basic theoretical concepts and key parameters for developing mathematical models that simulate the migration of alcohol sulfate into agricultural soils. Environ Toxicol Chem 2014;33:508–515. © 2013 SETAC more...
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- 2014
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21. Ultra high performance liquid chromatography–tandem mass spectrometry method for the determination of soluble milk glycans in rat serum
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Alberto Zafra-Gómez, A. Santos-Fandila, Maria Ramirez, E. Vazquez, Alberto Navalón, and Ricardo Rueda
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Detection limit ,Spectrometry, Mass, Electrospray Ionization ,Analyte ,Chromatography ,Molecular Structure ,Chemistry ,Electrospray ionization ,Selected reaction monitoring ,Mass spectrometry ,High-performance liquid chromatography ,Rats ,Analytical Chemistry ,Triple quadrupole mass spectrometer ,Rats, Sprague-Dawley ,Milk ,Polysaccharides ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Animals ,Female ,Chromatography, High Pressure Liquid - Abstract
The main objective of the present work was to develop and validate a multicompound method to measure soluble milk glycans (SMGs) in biological fluids such as serum. An ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the identification and quantification of the following SMGs and their precursors 2'-fucosyllactose, 3'-sialyllactose, 6'-sialyllactose, lacto-N-neotetraose, N-acetylneuraminic acid, fucose, lactose and glucose in rat serum samples was set up. These analytes were separated in an Acquity UPLC BEH Amide column using acetonitrile-water gradient with ammonia as additive, in a 10 min run, and were detected and quantified using a triple quadrupole (QqQ) mass spectrometer. The mass spectrometric conditions in negative electrospray ionization mode (ESI-) were individually optimized for each analyte to obtain maximum sensitivity in the Selected Reaction Monitoring (SRM) mode. Selection of two specific fragmentation reactions for each compound allowed simultaneous quantification and identification in one run, ensuring a high specificity of the method. The limits of detection (LODs) ranged from 5 to 70 ng mL(-1) and the limits of quantification (LOQs) from 20 to 200 ng mL(-1). The inter- and intra-day variability was lower than 15% and the recoveries ranged from 85% to 115%. A biological application of the method was also described, specifically the time-course of SMGs in rat serum after an oral challenge. more...
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- 2014
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22. A new treatment by dispersive liquid–liquid microextraction for the determination of parabens in human serum samples
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Alberto Zafra-Gómez, Isaac Rodríguez, L. Ballesteros, F. Vela-Soria, Oscar Ballesteros, Alberto Navalón, and Rafael Cela
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Serum ,Butylparaben ,chemistry.chemical_classification ,Preservative ,Chromatography ,Liquid Phase Microextraction ,Preservatives, Pharmaceutical ,Extraction (chemistry) ,Parabens ,Hydrogen-Ion Concentration ,Mass spectrometry ,Biochemistry ,Analytical Chemistry ,Solvent ,chemistry.chemical_compound ,chemistry ,Limit of Detection ,Liquid chromatography–mass spectrometry ,Solvents ,Humans ,Sulfatases ,Ethylparaben ,Chromatography, High Pressure Liquid ,Alkyl ,Glucuronidase - Abstract
Alkyl esters of p-hydroxybenzoic acid (parabens) are a family of compounds that have been in use since the 1920s as preservatives in cosmetic formulations, with one of the lowest rates of skin problems reported in dermatological patients. However, in the last few years, many scientific publications have demonstrated that parabens are weak endocrine disruptors, meaning that they can interfere with the function of endogenous hormones, increasing the risk of breast cancer. In the present work, a new sample treatment method is introduced based on dispersive liquid-liquid microextraction for the extraction of the most commonly used parabens (methyl-, ethyl-, propyl-, and butylparaben) from human serum samples followed by separation and quantification using ultrahigh performance liquid chromatography-tandem mass spectrometry. The method involves an enzymatic treatment to quantify the total content of parabens. The extraction parameters (solvent and disperser solvent, extractant and dispersant volume, pH of the sample, salt addition, and extraction time) were accurately optimized using multivariate optimization strategies. Ethylparaben ring (13)C6-labeled was used as surrogate. Limits of quantification ranging from 0.2 to 0.7 ng mL(-1) and an interday variability (evaluated as relative standard deviations) from 3.8 to 11.9 % were obtained. The method was validated using matrix-matched calibration standard and a spike recovery assay. Recovery rates for spiked samples ranged from 96 to 106 %, and a good linearity up to concentrations of 100 ng mL(-1) was obtained. The method was satisfactorily applied for the determination of target compounds in human serum samples. more...
- Published
- 2013
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23. Removal and degradation characteristics of quinolone antibiotics in laboratory-scale activated sludge reactors under aerobic, nitrifying and anoxic conditions
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José Luis Vilchez, Juan José González-López, Ernesto Hontoria, Alberto Navalón, N. Dorival-García, and Alberto Zafra-Gómez
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Environmental Engineering ,Sewage ,Chemistry ,Heterotroph ,General Medicine ,Quinolones ,Management, Monitoring, Policy and Law ,Ammonia monooxygenase ,Biodegradation ,Membrane bioreactor ,Nitrification ,Anoxic waters ,Redox ,Aerobiosis ,Anti-Bacterial Agents ,Microbiology ,Biodegradation, Environmental ,Bioreactors ,Activated sludge ,Environmental chemistry ,Waste Management and Disposal ,Water Pollutants, Chemical - Abstract
This work describes the removal of 6 quinolone antibiotics from wastewaters under different redox conditions (aerobic, nitrifying and anoxic) through batch experiments in laboratory scale activated sludge reactors using mixed liquor from a membrane bioreactor pilot plant (MBR). The main removal pathways for antibiotics from wastewaters involved in each treatment are described. Mass balances indicated that sorption on sludge played a dominating role in the elimination of antibiotics. Sorption potential depended on the redox conditions, being lower in nitrifying (Kd, 414-876 L kg(-1)) and anoxic (Kd, 471-930 L kg(-1)) sludge in comparison with aerobic sludge (Kd, 534-1137 L kg(-1)). Kd was higher for piperazinylic quinolones. Redox conditions also influenced biodegradation, a secondary pathway, which followed first-order kinetics with degradation rates constants ranging from 1.8·10(-3) to 8.2·10(-3) h(-1). Biodegradation rates under anoxic conditions were negligible. The experimental results have also demonstrated much higher removal efficiency by biodegradation (36.2-60.0%) under nitrifying conditions in comparison with aerobic conditions (14.9-43.8%). The addition of allylthiourea, an ammonia monooxygenase inhibitor, inhibited nitrification completely and reduced significantly the biodegradation of target antibiotics (16.5-29.3%). The residual biodegradation in the presence of allylthiourea may be due to the activity of heterotrophs in the enriched nitrifier culture. The removal of the selected antibiotics under the studied redox conditions depended significantly on the bacteria composition of the sludge. These results suggest that despite the known persistence of this group of antibiotics it is possible to enhance their degradation using nitrifying conditions, which at adequate working conditions as high SRT, typical in MBR, become a promising alternative for improving quinolones removal from environment. more...
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- 2013
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24. Analysis of quinolone antibiotic derivatives in sewage sludge samples by liquid chromatography–tandem mass spectrometry: Comparison of the efficiency of three extraction techniques
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Alberto Navalón, N. Dorival-García, F.J. Camino-Sánchez, José Luis Vilchez, and Alberto Zafra-Gómez
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Detection limit ,Chromatography ,Sewage ,Chemistry ,Electrospray ionization ,Liquid-Liquid Extraction ,Extraction (chemistry) ,Selected reaction monitoring ,Hydrogen-Ion Concentration ,Quinolones ,Reference Standards ,Mass spectrometry ,Anti-Bacterial Agents ,Analytical Chemistry ,Sonication ,Certified reference materials ,Limit of Detection ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Pressure ,Humans ,Microwaves ,Water Pollutants, Chemical ,Sludge ,Chromatography, Liquid - Abstract
This work presents a comparison of three extraction techniques –ultrasound-assisted extraction (USE), microwave-assisted extraction (MAE) and pressurized liquid extraction (PLE) – and evaluates their efficiency in the determination of quinolone antibiotics in sewage sludge samples. Extraction parameters for each technique were optimized using design of experiments, and the compounds were detected and quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS), operating in positive electrospray ionization (ESI) mode. The use of two selected reaction monitoring transitions for each compound allowed simultaneous quantification and identification in one run. Analytes were separated in less than 10 min. Marbofloxacin and cincophen were used as surrogates for amphoteric and acid quinolones, respectively. The limits of detection (LODs) were between 2 and 5n g g � 1 , and the limits of quantification (LOQs) were between 4 and 18 ng g � 1 for the various analytes. The inter- and intra-day variability was o 7%. Due to the absence of certified reference materials (CRMs), the method was validated using matrix-matched calibration and a recovery assay with spiked samples. Recovery rates were between 97.9% and 104.8%. Statistical comparison demonstrated no significant differences between the three extraction techniques. The methods were successfully applied for the determination of quinolones in sewage sludge samples collected from different wastewater treatments plants (WWTPs) located in the province of Granada (Spain). The analytical methods developed here may be useful for the development of more in-depth studies on the occurrence and fate of these commonly used pharmaceuticals in WWTPs and in the environment. more...
- Published
- 2013
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25. Determination of alcohol sulfates and alcohol ethoxysulfates in wastewater samples by liquid chromatography tandem mass spectrometry
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C. Fernández-Ramos, Oscar Ballesteros, Alberto Navalón, Alberto Zafra-Gómez, Rosario Blanc, and José Luis Vilchez
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Detection limit ,Electrospray ,chemistry.chemical_compound ,Chromatography ,Wastewater ,Liquid chromatography–mass spectrometry ,Chemistry ,Extraction (chemistry) ,Alcohol ,Mass spectrometry ,Effluent ,Spectroscopy ,Analytical Chemistry - Abstract
The work develops a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for the identification and quantification of alkyl homologues of alcohol sulfates (AS) and ethoxymers of alcohol ethoxysulfates (AES) in wastewaters. The method involves isolation and preconcentration of the analytes from the samples using solid-phase extraction (SPE) with SAX cartridges prior to their quantification by LC–MS/MS with electrospray (ESI) interface in negative mode. The limits of detection (LOD) found were 0.1 μg L− 1 for AS, and ranged from 0.2 to 0.5 μg L− 1 for AES. The limits of quantification (LOQ) ranged from 0.3 to 0.4 μg L− 1 for AS, and from 0.5 to 1.5 μg L− 1 for AES. The accuracy of the method was studied in terms of trueness and precision. Trueness was evaluated by using a spike recovery assay with spiked blank samples. Recoveries ranged from 96.0 to 102.8% for AS and from 93.4 to 105.1% for AES. Precision (in terms of inter- and intra-day RSD) was lower than 5% for AS and AES. Finally, the method was satisfactorily applied to the quantification of compounds in wastewater samples collected from a wastewater treatment plant (WWTP) located in the city of Granada (Spain). Data obtained showed that AS are present in concentration levels from 0.7 to 39.4 μg L− 1 in influent waters and from 1.1 to 8.1 μg L− 1 in effluent waters. As for AES, the amounts (sum of ethoxymers) found ranged from 0.7 to 24.0 μg L− 1 in influents and from 1.9 to 2.5 μg L− 1 in effluents. more...
- Published
- 2013
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26. Simultaneous determination of 13 quinolone antibiotic derivatives in wastewater samples using solid‐phase extraction and ultra performance liquid chromatography–tandem mass spectrometry
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José Luis Vilchez, N. Dorival-García, Samuel Cantarero, Alberto Navalón, and Alberto Zafra-Gómez
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Matrix (chemical analysis) ,Analyte ,Chromatography ,Chemistry ,Liquid chromatography–mass spectrometry ,Electrospray ionization ,Selected reaction monitoring ,Analytical chemistry ,Solid phase extraction ,Mass spectrometry ,High-performance liquid chromatography ,Spectroscopy ,Analytical Chemistry - Abstract
A simple, rapid, sensitive, accurate and reliable multiresidue method based on ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) is developed and validated for the simultaneous determination of 13 quinolone derivatives in urban wastewaters. The main parameters influencing the preliminary sample treatment and selective solid‐phase extraction procedure have been analyzed in order to optimize a suitable procedure for extraction of amphoteric and acidic quinolones in one single step. Matrix components of wastewater samples were significantly reduced and even eliminated. The mass spectrometric conditions in positive electrospray ionization (ESI) mode were individually optimized for each analyte to obtain maximum sensitivity in the Selected Reaction Monitoring (SRM) mode. Selection of two specific fragmentation reactions for each compound allowed simultaneous quantification and identification in one run, ensuring a high specificity of the method. The analytes were separated in less than 10 min. Marbofloxacin and cincophen were used as surrogates for amphoteric and acid quinolones, respectively. The limits of detection ranged from 0.02 to 0.04 ng mL − 1 and limits of quantification from 0.07 to 0.15 ng mL − 1 , while inter‐ and intra‐day variabilities were more...
- Published
- 2013
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27. Biomonitoring of 21 endocrine disrupting chemicals in human hair samples using ultra-high performance liquid chromatography-tandem mass spectrometry
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Alberto Zafra-Gómez, José Luis Vilchez, Alberto Navalón, R. Rodríguez-Gómez, Julia Martín, and Esteban Alonso
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Male ,Industrial growth ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,010501 environmental sciences ,Endocrine Disruptors ,Mass spectrometry ,01 natural sciences ,Liquid chromatography–mass spectrometry ,Adverse health effect ,Tandem Mass Spectrometry ,Biomonitoring ,Environmental Chemistry ,Humans ,0105 earth and related environmental sciences ,Detection limit ,Chromatography ,Chemistry ,010401 analytical chemistry ,Public Health, Environmental and Occupational Health ,General Medicine ,General Chemistry ,Pollution ,0104 chemical sciences ,Calibration ,Extraction methods ,Environmental Pollutants ,Female ,Ultra high performance ,Chromatography, Liquid ,Environmental Monitoring ,Hair - Abstract
Rapid industrial growth has increased human exposure to a large variety of chemicals with adverse health effects. These industrial chemicals are usually present in the environment, foods, beverages, clothes and personal care products. Among these compounds, endocrine disrupting chemicals (EDCs) have raised concern over the last years. In the present work, the determination of 21 EDCs in human hair samples is proposed. An analytical method based on the digestion of the samples with a mixture of acetic acid/methanol (20:80, v/v) followed by a solid-liquid microextraction and analysis by ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was developed and validated. The most influential parameters affecting the extraction method were optimized. The method was validated using matrix-matched calibration and recovery assays. Limits of detection ranged from 0.2 to 4 ng g −1 , limits of quantification from 0.5 to 12 ng g −1 , and inter- and intra-day variability was under 15% in all cases. Recovery rates for spiked samples ranged from 92.1 to 113.8%. The method was applied for the determination of the selected compounds in human hair. Samples were collected weekly from six randomly selected volunteers (three men and three women) over a three-month period. All the analyzed samples tested positive for at least one of the analyzed compounds. more...
- Published
- 2016
28. Polar stir bars for isolation and preconcentration of perfluoroalkyl substances from human milk samples prior to UHPLC-MS/MS analysis
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Alberto Zafra-Gómez, Alberto Navalón, José Luis Vilchez, Esteban Alonso, Julia Martín, and R. Rodríguez-Gómez
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Quality Control ,Clinical Biochemistry ,Silicones ,Fractional Precipitation ,010501 environmental sciences ,Endocrine Disruptors ,Sodium Chloride ,Tandem mass spectrometry ,01 natural sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Silicone ,Limit of Detection ,Tandem Mass Spectrometry ,Humans ,Sample preparation ,Solid phase extraction ,Dimethylpolysiloxanes ,General Pharmacology, Toxicology and Pharmaceutics ,Chromatography, High Pressure Liquid ,0105 earth and related environmental sciences ,Detection limit ,Fluorocarbons ,Chromatography ,Polydimethylsiloxane ,Milk, Human ,010401 analytical chemistry ,Solid Phase Extraction ,General Medicine ,Hydrogen-Ion Concentration ,0104 chemical sciences ,Medical Laboratory Technology ,Perfluorooctane ,Sulfonate ,chemistry ,Alkanesulfonic Acids ,Female ,Adsorption - Abstract
Background: A new method for the determination of four perfluoroalkyl carboxylic acids (from C5 to C8) and perfluorooctane sulfonate in human milk samples using stir-bar sorptive extraction-ultra-HPLC–MS/MS has been accurately optimized and validated. Methodology: Polydimethylsiloxane and polyethyleneglycol modified silicone materials were evaluated. Discussion: Overall, polyethyleneglycol led to a better sensitivity. After optimizing experimental variables, the method was validated reaching detection limits in the range of 0.05–0.20 ng ml-1; recovery rates from 81 to 105% and relative standard deviations fewer than 13% in all cases. The method was applied to milk samples from five randomly selected women. All samples were positive for at least one of the target compounds with concentrations ranging between 0.8 and 6.6 ng ml-1, being the most abundant perfluorooctane sulfonate. more...
- Published
- 2016
29. Improved sample treatment for the determination of bisphenol A and its chlorinated derivatives in sewage sludge samples by pressurized liquid extraction and liquid chromatography–tandem mass spectrometry
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N. Dorival-García, Alberto Zafra-Gómez, Alberto Navalón, and José Luis Vilchez
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Chromatography ,Sewage ,Chemistry ,Liquid-Liquid Extraction ,Extraction (chemistry) ,Selected reaction monitoring ,Reproducibility of Results ,Atmospheric-pressure chemical ionization ,Hydrogen-Ion Concentration ,Mass spectrometry ,Analytical Chemistry ,Activated sludge ,Phenols ,Limit of Detection ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Solvents ,Sewage treatment ,Benzhydryl Compounds ,Chlorine ,Sludge ,Chromatography, Liquid - Abstract
A selective, sensitive, robust and accurate method for the determination of bisphenol A (BPA) and its chlorinated derivatives in sewage sludge samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is presented. Prior to instrumental analysis, an extraction procedure using pressurized liquid extraction (PLE) was carried out in order to obtain the highest recoveries and improve sensitivity. After LC separation, the MS conditions, in negative atmospheric pressurized chemical ionization (APCI) mode, were individually optimized for each analyte to obtain maximum sensitivity in the selected reaction monitoring (SRM) mode. The use of two reactions for each compound allowed simultaneous quantification and identification in one run. The analytes were separated in less than 6 min. BPA-d(16) was used as internal standard. The limits of detection of the method ranged from 4 to 8 ng g(-1) and the limits of quantification from 14 to 26 ng g(-1), while inter- and intra-day variability was under 6% in all cases. Due to the absence of certified materials, the method was validated using matrix-matched calibration and a recovery assay with spiked samples. Recovery rates ranged from 97.7% to 100.6%. The method was satisfactorily applied for the determination BPA and its chlorinated derivatives in sewage sludge samples collected from wastewater treatment plants (WWTPs) located in the province of Granada (Spain). The sludge samples came from a conventional activated sludge (AS) plant and from a membrane bioreactor (MBR) pilot plant. more...
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- 2012
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30. Analysis of bisphenol A and its chlorinated derivatives in sewage sludge samples. Comparison of the efficiency of three extraction techniques
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Alberto Zafra-Gómez, José Luis Vilchez, Alberto Navalón, and N. Dorival-García
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Atmospheric-pressure chemical ionization ,Chemical Fractionation ,Mass spectrometry ,Sensitivity and Specificity ,Biochemistry ,Analytical Chemistry ,Sonication ,Phenols ,Tandem Mass Spectrometry ,Pressure ,Benzhydryl Compounds ,Microwaves ,Detection limit ,Chromatography ,Sewage ,Chemistry ,Organic Chemistry ,Selected reaction monitoring ,Extraction (chemistry) ,Reproducibility of Results ,General Medicine ,Hydrogen-Ion Concentration ,Certified reference materials ,Wastewater ,Environmental chemistry ,Linear Models ,Water Pollutants, Chemical ,Sludge ,Chromatography, Liquid - Abstract
This paper presents a comparison of three extraction techniques—ultrasound-assisted extraction, microwave-assisted extraction and pressurized liquid extraction—in order to evaluate their efficiency in the determination of bisphenol A and its chlorinated derivatives in sewage sludge samples. Extraction parameters for each technique were accurately optimized to achieve the highest recoveries. The selected compounds were detected and quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS), operating in negative atmospheric pressure chemical ionization (APCI) and in multiple reaction monitoring (MRM) mode. The analytes were separated in less than 6 min. BPA-d 16 was used as internal standard. Three selective, sensitive, robust and accurate analytical methods were developed. The limits of detection (LODs) of the methods ranged from 2 to 9 ng g −1 and the limits of quantification (LOQs) from 8 to 26 ng g −1 , while inter- and intra-day variability was under 6% in all cases. Given the absence of certified reference materials (CRMs), the methods were validated separately by using matrix-matched calibration and recovery assays with spiked samples. Recovery rates ranged from 97.7% to 103.1%. The sewage sludge samples used for experiments were collected from two different wastewater treatments plants (WWTPs) located in the province of Granada (South-East Spain). The statistical comparison of the methods demonstrated no statistically significant differences between the extraction techniques for the determination of BPA and chlorinated derivatives in sludge samples. more...
- Published
- 2012
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31. Determination of alcohol sulfates in wastewater treatment plant influents and effluents by gas chromatography-mass spectrometry
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C. Fernández-Ramos, Alberto Zafra-Gómez, José Luis Vilchez, Oscar Ballesteros, I. Jiménez-Díaz, Rosario Blanc, and Alberto Navalón
- Subjects
Detection limit ,Trimethylsilyl Compounds ,Chromatography ,Sulfates ,Solid Phase Extraction ,Wastewater ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,Surface-Active Agents ,chemistry.chemical_compound ,chemistry ,Limit of Detection ,Alcohols ,Environmental chemistry ,Humans ,Selected ion monitoring ,Solid phase extraction ,Gas chromatography ,Gas chromatography–mass spectrometry ,Derivatization ,Effluent ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
In the present paper, we developed an accurate method for the analysis of alcohol sulfates (AS) in wastewater samples from wastewater treatment plant (WWTP) influents and effluents. Although many methodologies have been published in the literature concerning the study of anionic surfactants in environmental samples, at present, the number of analytical methodologies that focus in the determination of AS by gas chromatography in the different environmental compartments is limited. The reason for this is that gas chromatography–mass spectrometry (GC–MS) technique requires a previous hydrolysis reaction followed by derivatization reactions. In the present work, we proposed a new procedure in which the hydrolysis and derivatization reactions take place in one single step and AS are directly converted to trimethylsilyl derivatives. The main factors affecting solid-phase extraction (SPE), hydrolysis/derivatization and GC–MS procedures were accurately optimised. Quantification of the target compounds was performed by using GC–MS in selected ion monitoring (SIM) mode. The limits of detection (LOD) obtained ranged from 0.2 to 0.3 μg L −1 , and limits of quantification (LOQ) from 0.5 to 1.0 μg L −1 , while inter- and intra-day variability was under 5%. A recovery assay was also carried out. Recovery rates for homologues in spiked samples ranged from 96 to 103%. The proposed method was successfully applied for the determination of anionic surfactants in wastewater samples from one WWTP located in Granada (Spain). Concentration levels for the homologues up to 39.4 μg L −1 in influent and up to 8.1 μg L −1 in effluent wastewater samples. more...
- Published
- 2012
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32. Determination of benzophenones in human placental tissue samples by liquid chromatography–tandem mass spectrometry
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F. Vela-Soria, Alberto Navalón, Alberto Zafra-Gómez, Mariana F. Fernández, Nicolás Olea, I. Jiménez-Díaz, Oscar Ballesteros, José Luis Vilchez, and R. Rodríguez-Gómez
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Analyte ,Placenta ,Ethyl acetate ,Atmospheric-pressure chemical ionization ,010501 environmental sciences ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,Benzophenones ,chemistry.chemical_compound ,Pregnancy ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Humans ,0105 earth and related environmental sciences ,Detection limit ,Chromatography ,010401 analytical chemistry ,Extraction (chemistry) ,Reproducibility of Results ,Drug Residues ,3. Good health ,0104 chemical sciences ,chemistry ,Standard addition ,Linear Models ,Female ,Chromatography, Liquid - Abstract
Benzophenones (BPs) are a family of compounds widely used to protect the skin and hair from UV irradiation. Despite human exposure to BPs through dermal application of products containing sunscreen agents and the increasing evidence that BPs are able to interfere with endocrine systems, few studies have examined the occurrence of BPs in humans. In this work, we propose a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine six BPs, namely, benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), benzophenone-6 (BP-6), benzophenone-8 (BP-8) and 4-hydroxybenzophenone (4-OH-BP) in human placental tissue samples. The method involves an extraction step of the analytes from the samples using ethyl acetate, followed by a clean-up step using centrifugation prior to their quantification by LC-MS/MS using an atmospheric pressure chemical ionization (APCI) interface in the positive mode. Benzophenone-d(10) (BP-d(10)) was used as surrogate. Found detection limits (LOD) ranged from 0.07 to 0.3 ng g(-1) and quantification limits (LOQ) from 0.3 to 1.0 ng g(-1), while inter- and intra-day variability was under 5%. The method was validated using standard addition calibration and a recovery assay. Recovery rates for spiked samples ranged from 98 to 104%. This method was satisfactorily applied for the determination of BPs in 16 placental tissue samples collected from women who live in Granada (Spain). more...
- Published
- 2011
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33. UNE-EN ISO/IEC 17025:2005 accredited method for the determination of 121 pesticide residues in fruits and vegetables by gas chromatography–tandem mass spectrometry
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José Luis Vilchez, Alberto Zafra-Gómez, Alberto Navalón, F.J. Camino-Sánchez, Oscar Ballesteros, J. Ruiz-García, and R. Bermúdez-Peinado
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Residue (complex analysis) ,Chromatography ,Pesticide residue ,Gas Chromatography/Tandem Mass Spectrometry ,Chemistry ,Selected reaction monitoring ,media_common.cataloged_instance ,Gas chromatography ,European union ,Mass spectrometry ,Quechers ,Food Science ,media_common - Abstract
A rapid, sensitive, accurate and reliable multiresidue method for quantification and confirmation of 121 common agricultural pesticides in fruits and vegetables by gas chromatography in tandem with mass spectrometry was developed, validated and applied to 1463 vegetable and fruit samples collected over one year from extensive greenhouse cultures in Almeria (Spain). Prior to instrumental analysis an extraction procedure, based on a sample extraction of multi-class analytes according to QuEChERS method (quick, easy, cheap, effective, rugged and safe) with some modifications was used. Mass spectrometric conditions were individually optimized for each analyte to achieve maximum sensitivity in the Selected Reaction Monitoring (SRM) mode. The scan times for each segment were between 0.8 and 1.0 s, with a maximum of 35 transitions per segment. Use of two reactions for each pesticide allowed simultaneous quantification and identification in one run. The pesticides were separated in less than 30 min. Recovery and precision were evaluated in nine representative matrices (tomato, pepper, lettuce, cucumber, eggplant, zucchini, melon, watermelon and apple). The mean recoveries ranged from 80% for thiometon to 116% for heptenophos, with relative standard deviations lower than 20% for all components. Only three pepper samples, one of tomato and one of cucumber had residues above the maximum allowable residue (0.01 mg kg −1 ) according to European Union directives. The method was accredited according to UNE-EN ISO/IEC 17025:2005 international standard. more...
- Published
- 2011
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34. Determination of Vecuronium Bromide in Pharmaceuticals: Development, Validation and Comparative Study of HPLC and CZE Analytical Methods
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Maria Inês Rocha Miritello Santoro, Erika Rosa Maria Kedor-Hackmann, Guillermo Montoya, Fabio Pereira Gomes, Alberto Navalón Montón, Pedro López García, Mercedes Aguilera Cabrera, and José L. Quero
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BLOQUEADORES NEUROMUSCULARES ,Chromatography ,Chemistry ,Sodium ,Monobasic acid ,Organic Chemistry ,Clinical Biochemistry ,chemistry.chemical_element ,Electrolyte ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,chemistry.chemical_compound ,Capillary electrophoresis ,medicine ,Quinine Sulfate ,Vecuronium bromide ,Acetonitrile ,medicine.drug - Abstract
Vecuronium bromide is a neuromuscular blocking agent used for anesthesia to induce skeletal muscle relaxation. HPLC and CZE analytical methods were developed and validated for the quantitative determination of vecuronium bromide. The HPLC method was achieved on an amino column (Luna 150 × 4.6 mm, 5 μm) using UV detection at 205 nm. The mobile phase was composed of acetonitrile:water containing 25.0 mmol L−1 of sodium phosphate monobasic (50:50 v/v), pH 4.6 and flow rate of 1.0 mL min−1. The CZE method was achieved on an uncoated fused-silica capillary (40.0 cm total length, 31.5 cm effective length and 50 μm i.d.) using indirect UV detection at 230 nm. The electrolyte comprised 1.0 mmol L−1 of quinine sulfate dihydrate at pH 3.3 and 8.0% of acetonitrile. The results were used to compare both techniques. No significant differences were observed (p > 0.05). more...
- Published
- 2011
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35. Matrix effect study in the determination of linear alkylbenzene sulfonates in sewage sludge samples
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Juan A. de Ferrer, Samuel Cantarero, Alberto Zafra-Gómez, C. Verge, Oscar Ballesteros, Alberto Navalón, and José Luis Vilchez
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Chromatography ,Sewage ,business.industry ,Linear alkylbenzene ,Health, Toxicology and Mutagenesis ,Extraction (chemistry) ,Chemical Fractionation ,Solvent ,chemistry.chemical_compound ,Adsorption ,Alkanesulfonic Acids ,chemistry ,Wastewater ,Environmental Chemistry ,Methanol ,business ,Water Pollutants, Chemical ,Sludge ,Chromatography, Liquid ,Environmental Monitoring - Abstract
We propose a study of the matrix effect in the determination of linear alkylbenzene sulfonates (LAS) in sewage sludge samples. First, a rapid, selective and sensitive method is proposed. The method involves two stages: the extraction of the compound from the samples and analysis by liquid chromatography with fluorescence detection (LC-FLD). Three different techniques of extraction (microwave-assisted extraction, Soxhlet, and ultrasounds) were compared, and microwave-assisted extraction was selected as the best suited for our purpose. Microwave-assisted extraction allows reducing the extraction time (25 min compared with 12 h for conventional Soxhlet extraction) and solvent waste (25 ml of methanol compared with 200 ml for Soxhlet or more than 50 ml for the ultrasonic procedure). Absence of matrix effect was evaluated with two standards (2ØC(8:0) and 2ØC(16:0) ) that are not commercial; therefore, neither of them was detected in sewage sludge samples and they showed similar environmental behavior (adsorption and precipitation) to LAS (C(11:0) -C(13.0) ), which allow us to evaluate the matrix effect. Validation was carried out by a recovery assay, and the method was applied to samples from different sources; therefore, they had different compositions. more...
- Published
- 2011
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36. Determination of Bisphenol A and its chlorinated derivatives in placental tissue samples by liquid chromatography–tandem mass spectrometry
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José Luis Vilchez, Alberto Navalón, Mariana F. Fernández, Alberto Zafra-Gómez, Nicolás Olea, I. Jiménez-Díaz, Oscar Ballesteros, and N. Navea
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Bisphenol A ,Placenta ,Clinical Biochemistry ,Atmospheric-pressure chemical ionization ,Endocrine Disruptors ,Tandem mass spectrometry ,Mass spectrometry ,Sensitivity and Specificity ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,chemistry.chemical_compound ,Phenols ,Pregnancy ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Hydrocarbons, Chlorinated ,Humans ,Benzhydryl Compounds ,Detection limit ,Chromatography ,Chemistry ,Reproducibility of Results ,Cell Biology ,General Medicine ,Standard addition ,Linear Models ,Female ,Chlorine Compounds ,Chromatography, Liquid - Abstract
The group of compounds commonly called endocrine disruptors covers a wide range of synthetic and natural substances able to alter the normal hormone function of wildlife and humans, consequently causing adverse health effects. Bisphenol A (BPA) and its chlorinated derivatives are some of these compounds. In this work, we propose a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine these compounds in human placental tissue samples. The method involves an extraction phase of the extracts from the samples using ethyl acetate, followed by a clean-up phase by centrifugation prior to their quantification by LC-MS/MS using an atmospheric pressure chemical ionization (APCI) interface in the negative mode. Deuterated Bisphenol A (BPA-d(16)) was used as internal standard. Found detection limits (DL) ranged from 0.2 to 0.6 ng g(-1) and quantification limits (QL) from 0.5 to 2.0 ng g(-1) for Bisphenol A and its chlorinated derivatives, while inter- and intra-day variability was under 8.1%. The method was validated using standard addition calibration and a spike recovery assay. Recovery rates for spiked samples ranged from 97% to 105%. This method was satisfactorily applied to the determination of BPA and its chlorinated derivatives in 49 placental tissue samples collected from women who live in the province of Granada (Spain). more...
- Published
- 2010
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37. UNE-EN ISO/IEC 17025:2005-accredited method for the determination of pesticide residues in fruit and vegetable samples by LC-MS/MS
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F.J. Camino-Sánchez, Alberto Navalón, G. Crovetto, José Luis Vilchez, Oscar Ballesteros, Alberto Zafra-Gómez, and B. Oliver-Rodríguez
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Spectrometry, Mass, Electrospray Ionization ,Analyte ,Health, Toxicology and Mutagenesis ,Food Contamination ,Toxicology ,Quechers ,Limit of Detection ,Tandem Mass Spectrometry ,Vegetables ,Chromatography, High Pressure Liquid ,Detection limit ,Residue (complex analysis) ,Chromatography ,Pesticide residue ,Chemistry ,Selected reaction monitoring ,Pesticide Residues ,Public Health, Environmental and Occupational Health ,Analytic Sample Preparation Methods ,Reproducibility of Results ,food and beverages ,General Chemistry ,General Medicine ,Pesticide ,Food Inspection ,ISO/IEC 17025 ,Europe ,Fruit ,Calibration ,Food Science - Abstract
A rapid, simple and sensitive multi-residue method was developed and validated for the simultaneous quantification and confirmation of 69 pesticides in fruit and vegetables using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted following the quick, easy, cheap, effective, rugged and safe method known as QuEChERS. Mass spectrometric conditions were individually optimised for each analyte in order to achieve maximum sensitivity in multiple reaction monitoring (MRM) mode. Using the developed chromatographic conditions, 69 pesticides can be separated in less than 17 min. Two selected reaction monitoring (SRM) assays were used for each pesticide to obtain simultaneous quantification and identification in one run. With this method in SRM mode, more than 150 pesticides can be analysed and quantified, but their confirmation is not possible in all cases according to the European regulations on pesticide residues. Nine common representative matrices (zucchini, melon, cucumber, watermelon, tomato, garlic, eggplant, lettuce and pepper) were selected to investigate the effect of different matrices on recovery and precision. Mean recoveries ranged from 70% to 120%, with relative standard deviations (RSDs) lower than 20% for all the pesticides. The proposed method was applied to the analysis of more than 2000 vegetable samples from the extensive greenhouse cultivation in the province of Almeria, Spain, during one year. The methodology combines the advantages of both QuEChERS and LC-MS/MS producing a very rapid, sensitive, accurate and reliable procedure that can be applied in routine analytical laboratories. The method was validated and accredited according to UNE-EN-ISO/IEC 17025:2005 international standard (accreditation number 278/LE1027). more...
- Published
- 2010
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38. Determination of insoluble soap in agricultural soil and sewage sludge samples by liquid chromatography with ultraviolet detection
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Alberto Zafra-Gómez, C. Verge, G. Crovetto, Alberto Navalón, Samuel Cantarero, Juan A. de Ferrer, Oscar Ballesteros, and José Luis Vilchez
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chemistry.chemical_classification ,Chromatography ,Sewage ,Health, Toxicology and Mutagenesis ,Potassium ,Extraction (chemistry) ,Salt (chemistry) ,chemistry.chemical_element ,Soil classification ,Soaps ,Potassium carbonate ,chemistry.chemical_compound ,chemistry ,Soil Pollutants ,Environmental Chemistry ,Calcium ,Magnesium ,Spectrophotometry, Ultraviolet ,Petroleum ether ,Derivatization ,Sludge ,Chromatography, Liquid - Abstract
We have developed a new analytical procedure for determining insoluble Ca and Mg fatty acid salts (soaps) in agricultural soil and sewage sludge samples. The number of analytical methodologies that focus in the determination of insoluble soap salts in different environmental compartments is very limited. In this work, we propose a methodology that involves a sample clean-up step with petroleum ether to remove soluble salts and a conversion of Ca and Mg insoluble salts into soluble potassium salts using tripotassium ethylenediaminetetraacetate salt and potassium carbonate, followed by the extraction of analytes from the samples using microwave-assisted extraction with methanol. An improved esterification procedure using 2,4-dibromoacetophenone before the liquid chromatography with ultraviolet detection analysis also has been developed. The absence of matrix effect was demonstrated with two fatty acid Ca salts that are not commercial and are never detected in natural samples (C13:0 and C17:0). Therefore, it was possible to evaluate the matrix effect because both standards have similar environmental behavior (adsorption and precipitation) to commercial soaps (C10:0 to C18:0). We also studied the effect of the different variables on the clean-up, the conversion of Ca soap, and the extraction and derivatization procedures. The quantification limits found ranged from 0.4 to 0.8 mg/kg. The proposed method was satisfactorily applied for the development of a study on soap behavior in agricultural soil and sewage sludge samples. Environ. Toxicol. Chem. 2010;29:2470-2476. # 2010 SETAC Keywords—Agricultural soil Sewage sludge Soap Microwave-assisted extraction Liquid chromatography more...
- Published
- 2010
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39. Improved sample treatment for the determination of insoluble soap in sewage sludge samples by liquid chromatography with fluorescence detection
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Alberto Zafra-Gómez, Samuel Cantarero, José Luis Vilchez, Alberto Navalón, J.A. de Ferrer, C. Verge, Oscar Ballesteros, and G. Crovetto
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Chromatography ,Sewage ,Potassium ,Extraction (chemistry) ,chemistry.chemical_element ,Analytical Chemistry ,Solvent ,chemistry.chemical_compound ,Spectrometry, Fluorescence ,chemistry ,Sample preparation ,Petroleum ether ,Methanol ,Microwaves ,Derivatization ,Sludge ,Chromatography, Liquid - Abstract
A new selective and sensitive method for the determination of insoluble fatty acid salts (soap) in sewage sludge samples is proposed. The method involves a clean up of sample with petroleum ether, the conversion of calcium and magnesium insoluble salts into soluble potassium salts, potassium salts extraction with methanol, and a derivatization procedure previous to the liquid chromatography with fluorescence detection (LC-FLD) analysis. Three different extraction techniques (Soxhlet, microwave-assisted extraction and ultrasounds) were compared and microwave-assisted extraction (MAE) was selected as appropriate for our purpose. This allowed to reduce the extraction time and solvent waste (50 mL of methanol in contrast with 250 mL for Soxhlet procedure). The absence of matrix effect was demonstrated with two standards (C(13:0) and C(17:0)) that are not commercials and neither of them has been detected in sewage sludge samples. Therefore, it was possible to evaluate the matrix effect since both standards have similar environmental behaviour (adsorption and precipitation) to commercial soaps (C(10:0)-C(18:0)). The method was successfully applied to samples from different sources and consequently, with different composition. more...
- Published
- 2010
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40. New sample treatment for the determination of alkylphenols and alkylphenol ethoxylates in agricultural soils
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José Luis Vilchez, C. Verge, Oscar Ballesteros, I. Jiménez-Díaz, Alberto Navalón, G. Crovetto, Alberto Zafra-Gómez, and J.A. de Ferrer
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Environmental Engineering ,Soil test ,Alkylphenol ,Health, Toxicology and Mutagenesis ,Mass spectrometry ,Gas Chromatography-Mass Spectrometry ,Soil ,chemistry.chemical_compound ,Phenols ,Soil Pollutants ,Environmental Chemistry ,Solid phase extraction ,Chromatography ,Chemistry ,Extraction (chemistry) ,Public Health, Environmental and Occupational Health ,Agriculture ,General Medicine ,General Chemistry ,Pollution ,Spain ,Environmental chemistry ,Soil water ,Ethylene Glycols ,Methanol ,Gas chromatography ,Environmental Monitoring - Abstract
A new sample treatment for alkylphenols (AP) and alkylphenol ethoxylates (APEO) determination in agricultural soil samples has been developed. In a first stage these compounds were isolated from soil by pressurized liquid extraction (PLE) using methanol. In a second stage the extracts were cleaned up and pre-concentrated by solid-phase extraction (SPE) using ENV + cartridges. The effect of different variables on PLE and SPE was also studied. In the last place, separation and quantification of analytes were performed by liquid chromatography with fluorescence detection (LC–FD) and gas chromatography coupled to mass spectrometry (GC–MS). Quantification limits (QL) ranged from 20 to 200 ng g −1 for LC–FD and from 3 to 126 ng g −1 for GC–MS. This method was satisfactorily applied in a study field designed to evaluate the environmental behaviour of APEOs in agricultural soils. more...
- Published
- 2010
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41. Characterization of sepia ink in ancient graphic documents by capillary electrophoresis
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José Luis Vilchez, Teresa Espejo, Ana López-Montes, Alberto Navalón, and Rosario Blanc
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Chromatography ,Capillary electrophoresis ,Inkwell ,Computer science ,Sepia ,Applied potential ,Diode array ,Spectroscopy ,Analytical Chemistry - Abstract
A simple and rapid capillary electrophoresis with diode array detection method was developed for sepia ink identification in ancient graphic documents. Separation was performed in a fused-silica capillary (64.5 cm length, 50 μm i.d.). The running buffer was 20 mM sodium tetraborate solution, pH 9.2. The applied potential was 25 kV, temperature 25 °C and detection was at 220 nm. An appropriate extraction procedure was applied for the take and treatment of sample from the reference substances and ancient graphic documents. This method was successfully applied to the collection of drawings and maps from the Royal Chancellery Archives of Granada (Spain). more...
- Published
- 2009
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42. Comparison of Solid-Phase Extraction and Solid-Phase Microextraction Using Octadecylsilane Phase for the Determination of Pesticides in Water Samples
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Alberto Navalón, Avismelsi Prieto, Lilia Araujo, and José Luis Vilchez
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Chromatography ,Chemistry ,Phase (matter) ,Solid phase extraction ,Pesticide ,Solid-phase microextraction ,Analytical Chemistry - Published
- 2009
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43. Simultaneous determination of quinolone antibacterials in bovine milk by liquid chromatography-mass spectrometry
- Author
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Alberto Zafra-Gómez, Luís E. García-Ayuso, Antonio Garballo, Alberto Navalón, and Oscar Ballesteros
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Spectrometry, Mass, Electrospray Ionization ,Danofloxacin ,Clinical Biochemistry ,Quinolones ,Biochemistry ,Analytical Chemistry ,Sarafloxacin ,Liquid chromatography–mass spectrometry ,Drug Discovery ,medicine ,Animals ,media_common.cataloged_instance ,Protein precipitation ,European union ,Molecular Biology ,Difloxacin ,media_common ,Pharmacology ,Chromatography ,Chemistry ,Elution ,Analytic Sample Preparation Methods ,General Medicine ,Anti-Bacterial Agents ,Milk ,Flumequine ,Cattle ,Chromatography, Liquid ,medicine.drug - Abstract
A new liquid chromatography–mass spectrometry (LC–MS) method has been developed and validated for the simultaneous determination of eight quinolone antibacterials for veterinary use in processed bovine milk samples. The quinolones studied included marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine. Also, a new sample-treatment procedure was used for extraction and preconcentration of these compounds. It involved defatting by centrifugation, protein precipitation by adding a mixture of glacial acetic acid–acetonitrile and removing acetonitrile with dichloromethane; finally, the acidified aqueous layer was evaporated to dryness in a speed vac system, resuspended in the mobile phase and filtered prior to LC injection. The mobile phase was composed of a formic acid aqueous solution 0.1% (v/v) and acetonitrile, with an initial composition of water–acetonitrile 95: 5 (v/v) and using linear gradient elution. Norfloxacin was used as internal standard. The limits of quantification found (2–7 ng g−1) were in all cases lower than the maximum residue limits tolerated by the European Union for these compounds in milk. Copyright © 2008 John Wiley & Sons, Ltd. more...
- Published
- 2008
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44. Determination of Sulfophenyl Carboxylic Acids in Agricultural Groundwater Samples by Liquid Chromatography with Fluorescence Detection
- Author
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Oscar Ballesteros, José Luis Vilchez, M. C. Fernández-Ramos, I. Jiménez-Díaz, A. Zafra, and Alberto Navalón
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chemistry.chemical_classification ,Detection limit ,Chromatography ,Linear alkylbenzene ,Carboxylic acid ,Biochemistry (medical) ,Clinical Biochemistry ,Extraction (chemistry) ,Biodegradation ,Biochemistry ,Fluorescence spectroscopy ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Environmental chemistry ,Electrochemistry ,Solid phase extraction ,Spectroscopy ,Groundwater - Abstract
We have developed an analytical method to determine six sulfophenyl carboxylic acids (SPC) in agricultural groundwater samples. It involves a solid-phase extraction (SPE) procedure and subsequent separation and determination using liquid chromatography with fluorescence detection (LC–FD).The quantification limits ranged between 0.7 and 1.2 ng ml−1. The proposed method was proved satisfactorily for the detection and determination of these compounds in groundwater samples during a study into the biodegradation of linear alkylbenzene sulfonates (LAS) in an agricultural soil sampled from the irrigated plain to the west of Granada (Spain). more...
- Published
- 2008
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45. Gas chromatographic–mass spectrometric study of the degradation of phenolic compounds in wastewater olive oil by Azotobacter Chroococcum
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Alberto Zafra-Gómez, José Luis Vilchez, Berta Luzón-Toro, Alberto Navalón, M.J.B. Juárez, Jose J. Gonzalez, and O.A. Ballesteros-García
- Subjects
Environmental Engineering ,Industrial Waste ,Bioengineering ,medicine.disease_cause ,Syringaldehyde ,Gas Chromatography-Mass Spectrometry ,chemistry.chemical_compound ,Phenols ,medicine ,Plant Oils ,Olive Oil ,Waste Management and Disposal ,Azotobacteraceae ,Chromatography ,biology ,Renewable Energy, Sustainability and the Environment ,food and beverages ,General Medicine ,Reference Standards ,Syringic acid ,biology.organism_classification ,chemistry ,Polyphenol ,Azotobacter ,Azotobacter chroococcum ,Gas chromatography ,Gas chromatography–mass spectrometry - Abstract
Compounds present in wastewater olive oil (WWOO) which can be used in metabolic pathways of Azotobacter chroococcum (A. chroococcum) have been investigated. Some compounds such as syringic acid, p-coumaric acid and syringaldehyde do not favour microorganism growing up. However, it has been shown that in batch culture, polyphenolic compounds (PCs) such as protocatetic acid and p-hydroxybenzoic acid do facilitate the growing up of microorganism. What is more, the maximum concentration in which bacteria can grow was 0.3% (w/v) for both polyphenols. At higher concentrations, substrate inhibition was observed; which is characterized by decreasing growth rates. Therefore, A. chroococcum can grow up using PCs as an individual source of carbon and energy supply but it is also dependent on the type of the compound and on its concentration. A gas chromatography coupled mass spectrometry method has been used for the study of the degradation of simple phenolic compounds. more...
- Published
- 2008
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46. Determination of some endocrine disrupter chemicals in urban wastewater samples using liquid chromatography–mass spectrometry
- Author
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Alberto Zafra-Gómez, José Luis Vilchez, Alberto Navalón, and Oscar Ballesteros
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Bisphenol A ,chemistry.chemical_compound ,Analyte ,Chromatography ,Wastewater ,chemistry ,Trace Amounts ,Liquid chromatography–mass spectrometry ,Extraction (chemistry) ,Phthalate ,Phenol ,Spectroscopy ,Analytical Chemistry - Abstract
An analytical method for the simultaneous determination of trace amounts of fourteen endocrine disrupter chemicals (EDCs) in urban wastewater samples has been developed. The studied compounds were: bisphenol A and its chlorinated derivatives (monochloro, dichloro, trichloro and tretrachlorobisphenol A), three alkylphenols (4-n-nonyl, 4-n-octyl and 4-(tert-octyl)phenol) and six well known phthalate esters (dimethyl, diethyl, di-n-butyl, butylbenzyl, bis(2-ethylhexyl) and di-n-octylphthalate). The method involves extraction from the samples and preconcentration of the analytes using a solid-phase extraction (SPE) procedure and subsequent liquid chromatographic separation with mass spectrometric detection (LC−MS). Bisphenol F was used as a surrogate. Quantification limits found ranged between 12 ng L− 1 for diethylphthalate and 69 ng L− 1 for 4-(tert-octyl)phenol. The method was satisfactorily used for determination of these chemicals in urban wastewater samples of Granada City (Spain) and validated using a recovery assay with spiked samples. more...
- Published
- 2008
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47. Determination of sulfophenyl carboxylic acids in agricultural groundwater samples by CE with ultraviolet absorption detection
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Alberto Navalón, José Luis Vilchez, Oscar Ballesteros, and I. Jiménez-Díaz
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Agricultural irrigation ,Chromatography ,Cetrimonium ,Linear alkylbenzene ,Solid Phase Extraction ,Clinical Biochemistry ,Electrophoresis, Capillary ,Reproducibility of Results ,Agriculture ,Ultraviolet absorption ,Buffer solution ,Biodegradation ,Online Systems ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Acetic acid ,Alkanesulfonic Acids ,chemistry ,Cetrimonium Compounds ,Spectrophotometry, Ultraviolet ,Ammonium acetate ,Water Pollutants, Chemical ,Groundwater - Abstract
An analytical method for the determination of six sulfophenyl carboxylic acids, namely (p-sulfophenyl)acetic, 2-(p-sulfophenyl)propionic, 2-(p-sulfophenyl)butyric, 3-(p-sulfophenyl)butyric, 4-(p-sulfophenyl)butyric, and 5-(p-sulfophenyl)valerianic acid, in agricultural irrigation water samples was developed. It involves an SPE procedure, an on-line preconcentration normal stacking mode and subsequent separation and determination using CE with UV detection (CE-UV). p-Sulfobenzoic acid was used as internal standard. The compounds were separated with an uncoated capillary and a 25 mM ammonium acetate/acetic acid buffer solution (pH 5.5) with 2-propanol (30% v/v) and 0.75 mM CTAB. Analyses were run at -25 kV, 25 degrees C, and 100 s of hydrodynamic injection with UV detection at 225 nm. Quantification limits found ranged between 4 and 6 ng/mL. The proposed method was validated using a recovery assay. It was satisfactorily used for the determination of these compounds in groundwater samples to track down the biodegradation of linear alkylbenzene sulfonates in an agricultural soil from the fertile plain of Granada (Spain). more...
- Published
- 2008
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- View/download PDF
48. Multiresidue method for simultaneous determination of quinolone antibacterials in pig kidney samples by liquid chromatography with fluorescence detection
- Author
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M.K. Hassouan, Alberto Navalón, José Luis Vilchez, A. Zafra, and Oscar Ballesteros
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Detection limit ,Chromatography ,Swine ,Chemistry ,Danofloxacin ,Elution ,Clinical Biochemistry ,Cell Biology ,General Medicine ,Quinolones ,Kidney ,Biochemistry ,High-performance liquid chromatography ,Anti-Bacterial Agents ,Analytical Chemistry ,Sarafloxacin ,Flumequine ,medicine ,Animals ,media_common.cataloged_instance ,European union ,Chromatography, High Pressure Liquid ,Difloxacin ,medicine.drug ,media_common - Abstract
A new analytical method for simultaneous determination of eight quinolones namely, ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, oxolinic acid and sarafloxacin, in pig kidney samples was developed. The procedure involves the extraction of the quinolones from the samples by traditional extraction, a step for clean-up and preconcentration of the analytes by solid-phase extraction (SPE) and subsequent liquid chromatography separation with fluorescence detection (LC–FD). The mobile phase was composed of acetonitrile and 10 mM citrate buffer solution of pH 4.5, with an initial composition of acetonitrile–water 12:88 (v/v) and using linear gradient elution. Norfloxacin was used as internal standard. The limits of detection (1–8 μg kg −1 ) and the limits of quantification (5–27 μg kg −1 ) found were lower than the maximum residue limits regulated by the European Union for these compounds in pig kidney. more...
- Published
- 2007
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49. Differentiation of Green, White, Black, Oolong, and Pu-erh Teas According to Their Free Amino Acids Content
- Author
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J. M. Jurado, Ángela Alcázar, M. J. Martín, Fernando de Pablos, Oscar Ballesteros, Alberto Navalón, and J L Vilches
- Subjects
Alanine ,chemistry.chemical_classification ,Chromatography ,Tea ,Phenylalanine ,General Chemistry ,Theanine ,Amino acid ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Aspartic acid ,Neural Networks, Computer ,Asparagine ,Amino Acids ,Leucine ,Isoleucine ,General Agricultural and Biological Sciences ,Chromatography, High Pressure Liquid - Abstract
In this paper, the differentiation of green, black, Oolong, white, and Pu-erh teas has been carried out according to their free amino acid contents. Alanine, arginine, asparagine, aspartic acid, glutamic acid, isoleucine, histidine, leucine, phenylalanine, serine, theanine, threonine, and tyrosine have been determined by liquid chromatography with derivatization with o-phthalaldehyde and fluorescence detection. The chromatographic separation was achieved with a Hypersil ODS column and gradient elution. The amino acid contents were used as chemometric descriptors for classification purposes of different tea varieties. Principal component analysis, k-nearest neighbors, linear discriminant analysis, and artificial neural networks were applied to differentiate tea varieties. Using back-propagation multilayer perceptron artificial neural networks, 100% success in the classification was obtained. The most differentiating amino acids were glutamic acid, asparagine, serine, alanine, leucine, and isoleucine. more...
- Published
- 2007
- Full Text
- View/download PDF
50. Characterization of aniseed-flavoured spirit drinks by headspace solid-phase microextraction gas chromatography–mass spectrometry and chemometrics
- Author
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Ángela Alcázar, Fernando de Pablos, M. J. Martín, Alberto Navalón, José Luis Vilchez, Oscar Ballesteros, and J. M. Jurado
- Subjects
Chemometrics ,chemistry.chemical_compound ,Chromatography ,chemistry ,Extraction (chemistry) ,Estragole ,Sample preparation ,Gas chromatography ,Gas chromatography–mass spectrometry ,Mass spectrometry ,Solid-phase microextraction ,Analytical Chemistry - Abstract
The volatile composition of aniseed-flavoured spirit drinks was studied by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The influence of the time, temperature, volume of sample and ionic strength on the extraction were considered. Several aniseed-flavoured spirit drinks, such as pastis, sambuca, anis and raki were analyzed. The major compounds found were trans-anethole (41.22-98%), cis-anethole (0.77-18.65%) and estragole (0.1-17.96%). gamma-Himachalene (0-28.07%) and alpha-himachalene (0-4.8%) were also present in anis and raki beverages. The compounds determined were used as chemical descriptors to differentiate the four types of beverages considered. Principal component analysis (PCA), linear discriminant analysis (LDA) and artificial neural networks (ANN) were used as chemometric tools for characterization purposes. more...
- Published
- 2007
- Full Text
- View/download PDF
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