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In this study, the application of different nanomaterials as dispersants in matrix solid phase dispersion has been evaluated for the extraction of fifteen phthalates from different environmental samples prior to their separation and quantification by ultra-high performance liquid chromatography coupled to triple quadrupole mass spectrometry. Within the evaluated nanomaterials, including graphene oxide, multi-walled carbon nanotubes and iron 1,3,5-benzenetricarboxylate metal-organic framework, the last one showed the best results in terms of extraction capacity and sample clean-up. The effects of the different parameters affecting the sample pretreatment efficiency were exhaustively evaluated. The whole methodology was validated for agricultural soil and sand, using dibutyl phthalate-3,4,5,6-d 4 as surrogate. Recovery values ranged from 70 to 120% for both matrices with RSD values lower than 20% and the limits of quantification of the method achieved were in the range 0.14-2.7 μg/kg dry weight. Finally, the analysis of soil samples from different locations of Tenerife (Canary Islands, Spain) was carried out finding the presence of BBP, DIBP and DBP in the range 5-52 μg/kg dry weight in agricultural soils, and DIPP, DNOP and DINP in the range 2-101 μg/kg dry weight in sand samples., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A microdispersive solid-phase extraction method has been developed using multiwalled carbon nanotubes of 110-170 nm diameter and 5-9 μm length for the extraction of a group of nine phthalic acid esters (i.e., bis(2-methoxyethyl) phthalate, bis-2-ethoxyethyl phthalate, dipropyl phthalate, butylbenzyl phthalate, bis-2-n-butoxyethyl phthalate, bis-isopentyl phthalate, bis-n-pentyl phthalate, dicyclohexyl phthalate, and di-n-octyl phthalate) from tap water as well as from different beverages commercialized in plastic bottles (mineral water, lemon- and apple-flavored mineral water, and an isotonic drink). Determination was carried out by high-performance liquid chromatography coupled to mass spectrometry. The extraction procedure was optimized following a step-by-step approach, being the optimum extraction conditions: 50 mL of each sample at pH 6.0, 80 mg of sorbent, and 25 mL of acetonitrile as elution solvent. To validate the methodology, matrix-matched calibration and a recovery study were developed, obtaining determination coefficients >0.9906 and absolute recovery values between 70 and 117% (with relative standard deviations < 17%) in all cases. The limits of quantification of the method were between 0.173 and 1.45 μg/L. After the evaluation of the matrix effects, real samples were also analyzed, finding butylbenzyl phthalate in all samples (except in apple-flavored mineral water), though at concentrations below its limit of quantification of the method., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this work, a simple and environmental friendly methodology has been developed for the analysis of a group of six mycotoxins with estrogenic activity produced by Fusarium species (i.e. zearalanone, zearalenone, α-zearalanol, β-zearalanol, α-zearalenol, and β-zearalenol), using microdispersive SPE the symbol micro should de before dSPE with multiwalled carbon nanotubes as sorbent. Separation, determination, and quantification were achieved by HPLC coupled to ion trap MS with an ESI interface. Parameters affecting the extraction efficiency of µ-dSPE such as pH of the sample, amount of multiwalled carbon nanotubes, and type and volume of elution solvent, were studied and optimized. The methodology was validated for mineral, pond, and wastewater as well as for powdered infant milk using 17β-estradiol-2,4,16,16,17-d5 (17β-E2 -D5 ) as internal standard, obtaining recoveries ranging from 85 to 120% for the three types of water samples and from 77 to 115% for powdered infant milk. RSD values were lower than 10%. The LOQs achieved were in the range 0.05-2.90 μg/L for water samples and 2.02-31.9 μg/L for powdered infant milk samples., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this work, core-shell Fe3O4@poly(dopamine) magnetic nanoparticles (m-NPs) were prepared and characterized in our laboratory and applied as sorbents for the magnetic-micro solid phase extraction (m-μSPE) of twelve estrogenic compounds of interest (i.e. 17α-estradiol, 17β-estradiol, estrone, hexestrol, 17α-ethynylestradiol, diethylstibestrol, dienestrol, zearalenone, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol) from different water samples. Separation, determination and quantification were achieved by high-performance liquid chromatography coupled to ion trap mass spectrometry with electrospray ionization. NPs@poly(dopamine) were synthesized by a chemical coprecipitation procedure and characterized by different surface characterization techniques (X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy, infrared and Raman spectroscopy, vibrating sample magnetometry, microelectrophoresis and adsorption/desorption isotherms). Parameters affecting the extraction efficiency of m-μSPE (i.e. polymerization time, pH of the sample, extraction and elution conditions) were studied and optimized. The methodology was validated for Milli-Q, mineral, tap and wastewater using 2-methoxyestradiol as internal standard, obtaining recoveries ranging from 70 to 119% with relative standard deviation values lower than 20% and limits of quantification in the range 0.02-1.1 μg/L., (Copyright © 2015 Elsevier B.V. All rights reserved.)

In this manuscript, a dispersive SPE method based on the use of multiwalled carbon nanotubes has been developed for the determination of 15 organophosphorus pesticides residues including some of their metabolites (disulfoton sulfoxide, ethoprophos, cadusafos, dimethoate, terbufos, disulfoton, chlorpyrifos-methyl, malaoxon, fenitrothion, pirimiphos-methyl, malathion, chlorpyrifos, terbufos sulfone, disulfoton sulfone, and fensulfothion) from real environmental waters (run-off, mineral and tap water) by GC with nitrogen phosphorus detection. Factors that affect the enrichment efficiency such as sample volume, multiwalled carbon nanotubes amount, and volume of eluent were studied. The optimized method was validated in terms of matrix-matched calibration, recovery, precision, and accuracy for the three analyzed samples. In this last case, the developed Student's t test demonstrated that there were no significant differences between real and spiked concentrations. Optimum dispersive SPE conditions (extraction of 200 mL of water, pH 6.0, with 130 mg of multiwalled carbon nanotubes, elution with 25 mL of dichloromethane for run-off and tap water and 30 mL for mineral water) allowed the quantitative extraction of analytes at levels lower than the maximum residues limits legislated by the European Union, with LODs between 1.16 and 93.6 ng/L. Absolute recovery values achieved were in the range of 67-107% (RSD values <10.1%)., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The present work describes a method based on solid-phase extraction (SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for the simultaneous determination of three quinolones (pipemidic acid, oxolinic acid and flumequine) and twelve fluoroquinolones (marbofloxacin, fleroxacin, pefloxacin, levofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, danofloxacin, lomefloxacin, difloxacin, sarafloxacin, and moxifloxacin) in different infant and young children powdered milks. After suitable deproteination of the reconstituted powdered samples, a SPE procedure was developed providing recovery values higher than 84% (RSDs lower than 13%) for all the analytes, with limits of detection between 0.04 and 0.52 μg/kg. UPLC-MS/MS analyses were carried out in less than 10 min. Sixteen infant and young children powdered milk samples of different origin, type and composition bought at Spanish markets were analyzed. Residues of the selected antibiotics were not detected in any of the analyzed samples., (Copyright © 2011 Elsevier B.V. All rights reserved.)

In this work, a new method for the determination of eleven quinolone antibiotics (moxifloxacin, lomefloxacin, danofloxacin, ciprofloxacin, levofloxacin, marbofloxacin, enrofloxacin, difloxacin, pefloxacin, oxolinic acid and flumequine) in different water samples using dispersive solid-phase extraction (dSPE) and capillary zone electrophoresis with diode-array detection was developed. Oxidized multi-walled carbon nanotubes (o-MWCNTs) were used for the first time as stationary phases for the off-line preconcentration by dSPE of the antibiotics. A 65 mM phosphate buffer at pH 8.5 was found adequate for analyte separation while large volume sample stacking with polarity switching of the analytes dissolved in water containing 10% (v/v) of acetonitrile was carried out in order to improve the sensitivity. dSPE parameters, such as sample volume and pH, o-MWCNT amount, volume and type of eluent in dSPE were optimized. Application of the developed method to the analysis of spiked Milli-Q, mineral, tap, and wastewater samples resulted in good recoveries values ranging from 62.3 to 116% with relative standard deviation values lower than 7.7% in all cases. Limits of detection were in the range of 28-94 ng/L. The proposed method is very fast, simple, repeatable, accurate and highly selective., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Since the first report in 1991, carbon nanotubes (CNTs) have shown great possibilities for a wide variety of processes and applications, which include their use as electrodes, sensors (gas, enzymatic, etc.), nanoprobes, electronic materials, field emitters, etc. The combination of structures, dimensions and topologies has provided physical and chemical attractive properties that are unparalleled by most known materials. Their applications have also reached the Analytical Chemistry field in which CNTs are being used as matrices in matrix assisted laser desorption ionization, stationary phases in either gas chromatography, high performance liquid chromatography or capillary electrochromatography, also as pseudostationary phases in capillary electrophoresis, etc. as well as new solid-phase extraction (SPE) materials. Concerning this last application the number of works has considerably increased in the last five years. This review article pretends to focus on the most important features and different applications of SPE using CNTs (including matrix solid-phase dispersion and solid-phase microextraction) covering articles published since their introduction up to now (September 2009)., (Copyright 2009 Elsevier B.V. All rights reserved.)

This paper describes the use of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIm-BF(4)) as mobile phase additive for the analysis by high-performance liquid chromatography with fluorescence detection of a group of seven basic fluoroquinolone antibiotics (i.e. fleroxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin and difloxacin) in different milk samples. EMIm-BF(4) was found superior to 1-butyl-3-methylimidazolium tetrafluoroborate for the separation of the analytes from chromatographic interferences of the sample matrix. The optimized method was applied to the analysis of ovine, caprine and bovine milk, in the last case in either skimmed, semi-skimmed and full-cream milk after suitable acidic deproteination followed by a solid-phase extraction procedure. Recovery values between 73% and 113% were obtained for the three types of bovine milk samples, as well as for ovine and caprine milk (RSDs below 16% in all cases), which clearly demonstrates the applicability of the method to the three types of milk irrespective of the fat content of the samples. Limits of detection were in the range of 0.5-8.1 microg/L (approximately 0.5-25.9 microg/kg), well below the maximum residue limits established for these compounds by the current European legislation. A screening study of 24 different milk samples was also developed. In none of the samples, residues of the selected antibiotics were found.

Multi-walled carbon nanotubes (MWCNTs) have been used for the first time as solid-phase extraction (SPE) sorbents for the extraction of eight organophosphorus pesticides (i.e. ethoprophos, diazinon, chlorpyriphos-methyl, fenitrothion, malathion, chlorpyriphos, fenamiphos and buprofezin) from different commercial fruit juices (i.e. apple, grape, orange and pineapple). The developed method, which involves SPE and direct gas chromatography with nitrogen phosphorus detection analysis, is very fast, simple and cheap: only 1:1 dilution with Milli-Q water and pH adjustment to 6.0 of 10 mL of juice is necessary prior to a quick MWCNTs-SPE procedure that used only 40 mg of stationary phase (MWCNTs of 10-15 nm o.d., 2-6 nm i.d. and 0.1-10 microm length). Mean recovery values were above 73% for all the pesticides and fruit juices (between 77 and 101% for apple juice, 75 and 103% for grape juice, 73 and 103% for orange juice and 73 and 93% for pineapple juice) with a relative standard deviation (RSD) lower than 8.5% in all cases. Matrix matched calibration was carried out for each sample matrix since statistical differences between the calibration curves constructed is pure solvent and in the reconstructed juice extracts were found. Limits of detection ranged between 1.85 and 7.32 microg/L (which also represents LODs between 1.85 and 7.34 microg/kg) well below the European Union maximum residue limits for the raw fruits. The proposed method, which is demonstrated to be quick, cheap, accurate and highly selective, was also applied to the analysis of this group of pesticides in several commercial juices in which none of the selected pesticides were found.

In this work an analytical method for the determination of abamectin residues in avocados is developed using high-performance liquid chromatography (HPLC) with fluorescence (FL) detection. A pre-column derivatization with trifluoroacetic anhydride (TFAA) and N-methylimidazole (NMIM) was carried out. The mobile phase consisted of water, methanol and acetonitrile (5:47.5:47.5 v/v/v) and was pumped at a rate of 1 mL/min (isocratic elution). The fluorescence detector was set at an excitation wavelength of 365 nm and an emission wavelength of 470 nm. Homogenized avocado samples were extracted twice with acetonitrile:water 8:2 (v/v) and cleaned using C(18) solid-phase extraction (SPE) cartridges. Recovery values were in the range 87-98% with RSD values lower than 13%. The limits of detection (LODs) and quantification (LOQs) of the whole method were 0.001 and 0.003 mg/kg, respectively. These values are lower than the maximum residue limit (MRL) established by the European Union (EU) and the Spanish legislation in avocado samples.

In this work, a new multiresidue analytical method based on MEKC with UV detection combined with SPE as off-line preconcentration strategy, and reversed-electrode polarity stacking mode (REPSM) as on-line stacking procedure, has been developed for the monitoring of 12 pesticides (carbendazim, pirimicarb, metalaxyl, pyrimethanil, procymidone, nuarimol, azoxystrobin, tebufenozide, fenarimol, benalaxyl, penconazole, and tetradifon) that are currently being used in the Canary Islands (Spain). The optimized MEKC buffer, consisting of 100 mM sodium tetraborate and 30 mM SDS at pH 8.5 with 6% v/v 1-propanol, provided baseline resolution of the 12 pesticides in less than 20 min. The developed method was applied to the analysis of mineral, stagnant, and tap water samples. The proposed SPE-REPSM-MEKC-UV method showed high extraction efficiencies with detection limits (LODs) at the low ng/L level providing LOD values down to 64 ng/L for these real samples.

In this work, the development of a simple, fast and reliable method for the evaluation of a group of twelve plastic migrants in alcoholic and non-alcoholic beverages widely consumed by the population has been carried out. For that, a modified QuEChERS method for the extraction and preconcentration of the target compounds has been used prior to their separation and quantification by gas chromatography coupled to triple quadrupole tandem mass spectrometry. The whole methodology was validated for beer, cider and grape juice matrices, using dibutyl phthalate-3,4,5,6-d4 as surrogate. Recovery ranged from 75 to 120% for all matrices with relative standard deviation values lower than 20%, and the limits of quantification of the method were achieved in the range 0.034–1.415 μg/L. Finally, the analysis of different beer, cider and grape juice samples commercialised in different supermarkets of Tenerife was carried out, finding the presence of four of the evaluated phthalates in the range 0.14–1.1 μg/L in some of the evaluated beers, six of them in several cider samples, in the range 0.3–2.1 μg/L, and one in the range 1.2–1.5 μg/L in three of the analysed grape juices. [ABSTRACT FROM AUTHOR]

Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 μg/L (0.2-6.0 μg/kg dry weight) and 0.02-0.90 μg/kg (0.2-6.0 μg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 μg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens. [ABSTRACT FROM AUTHOR]

In this work, we have compared the selectivity of two commercial molecularly imprinted polymers (AFFINIMIP®SPE Estrogens and AFFINIMIP®SPE Zearalenone) for the extraction of 12 estrogenic compounds of interest (i.e. 17α-estradiol, 17β-estradiol, estrone, hexestrol, 17α-ethynylestradiol, diethylstibestrol, dienestrol, zearalenone, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol) from different water samples. High-performance liquid chromatography coupled with ion trap mass spectrometry with electrospray ionization was used for their determination. Results showed that although both molecularly imprinted polymeric cartridges were specifically designed for different groups of analytes (natural estrogens like estradiol in the first case and zearalenone derivatives in the second) they nearly have the same extraction performance (with recovery values in the range 65-101%) for the same analytes in Milli-Q water because of the cross-reactivity of the polymer. However, when more complex water samples were analyzed, it was clear that the behavior was different and that the AFFINIMIP®SPE Estrogens showed less cross-reactivity than the other cartridge. Validation of the proposed methodology with both cartridges revealed that the extraction was reproducible and that the final limits of detection of the proposed method were in the low ng/L range. [ABSTRACT FROM AUTHOR]

The article focuses on the new applications of carbon nanotubes (CNTs) in sample preparation and chromatography. It cites various properties of CNTs which make them useful in analytical sciences, such as sorption capacity, thermal and chemical stability. It cites various uses of CNTs including liquid chromatography (LC), capillary electrophoresis (CE), and solid-phase micro-extraction (SPME). INSET: KEY POINTS.

In this work, four ionic liquids differing in the length of the alkyl chain on the imidazolium cation and one ionic liquid containing tetraethylammonium, all with the same counterion, (i.e. 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIm-BF4), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIm-BF4), 1-hexyl-3-methylimidazolium tetrafluoroborate (HMIm-BF4), 1-methyl-3-octylimidazolium tetrafluoroborate (MOIm-BF4), and tetraethylammonium tetrafluroborate (Et4N-BF4)) were tested as mobile phase additives for HPLC separation of a group of seven basic fluoroquinolone (FQ) antibiotics for human and veterinary use (i.e. fleroxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, and difloxacin) using a conventional reversed-phase Nova-Pak C18 column. Fluorescence detection was used. Among the ionic liquids selected, use of BMIm-BF4 enabled effective separation of these compounds with relatively low analysis time (14 min). The best separation was achieved by isocratic elution at 1 mL min−1 with 5 mmol L−1 BMIm-BF4 and 10 mmol L−1 ammonium acetate at pH 3.0 with 13% ( v/ v) acetonitrile. Limits of detection (LODs) for fluorescence detection were in the range 0.5–11 μg L−1. The method was tested by analyzing several water samples after the optimization of a suitable solid-phase extraction (SPE) procedure using Oasis HLB cartridges. Mean recovery values were above 84% for all analytes with LODs in the range 1–29 ng L−1. [ABSTRACT FROM AUTHOR]

Abstract In the present work, a commercial metal-organic framework (Basolite® F300) has been applied for the first time as dispersive solid-phase extraction (dSPE) sorbent of eight phthalic acid esters (PAEs) (butyl benzyl phthalate, bis-2- n -butoxyethyl phthalate, bis-isopentyl phthalate, bis- n -pentyl phthalate, dicyclohexyl phthalate, di-(2-ethylhexyl) phthalate -DEHP-, di- n -octyl phthalate and diisononyl phthalate) and an adipate (bis (2-ethylhexyl) adipate), which is utilized as a PAE substitutive. Milli-Q, pond, tap and waste water were selected as samples. Dihexyl phthalate-3,4,5,6-d 4 was used as procedural internal standard. High-performance liquid chromatography mass spectrometry was used for the determination of the target compounds. Optimum dSPE conditions were the following: 50 mL of the water sample (pH 6.0), 120 mg of sorbent and 15 mL of ACN as elution solvent. For the validation of the method, matrix-matched calibration and trueness of the method were addressed, obtaining determination coefficients (R2) higher than 0.9905 and relative recovery values between 70 and 118 % (RSDs < 20 %). The limits of quantification of the method were in the range 22–69 ng/L. Matrix effects were also studied. Different real samples were analysed, finding DEHP in all of them at the low µg/L level. Graphical abstract fx1 Highlights • Basolite® F300 metal-organic framework was used for the dSPE of phthalates from water. • LC-IT-MS was used as separation and detection technique. • Recovery values between 70 and 118 % (RSDs < 20 %) were obtained in all cases. • The limits of quantification of the method were in the range 22–69 ng/L. • The analysis of real samples revealed the presence of DEHP at the low µg/L level. [ABSTRACT FROM AUTHOR]

In this work, the suitability of Fe 3 O 4 nanoparticles coated with reduced-graphene oxide as sorbent was evaluated for the extraction of a group of fourteen phthalic acid esters (i.e. benzylbutyl phthalate (BBP), bis-2- n -butoxyethyl phthalate (DBEP), dibutyl phthalate (DBP), diisobutyl phthalate (DIBP), dicyclohexyl phthalate (DCHP), bis-2-ethoxyethyl phthalate (DEEP), diisodecyl phthalate (DIDP), diisononyl phthalate (DINP), bis-isopentyl phthalate (DIPP), bis-(2-methoxyethyl) phthalate (DMEP), dimethyl phthalate (DMP), di- n -octyl phthalate (DNOP), bis- n -pentyl phthalate (DNPP), dipropyl phthalate (DPP)) from environmental samples. Extraction was carried out using magnetic-micro dispersive solid-phase extraction while separation, identification and quantification of the target analytes were achieved by ultra-high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry. The methodology was validated for three different types of water samples using dibutyl phthalate-3,4,5,6-d 4 as internal standard for all of them. Recovery values ranged from 70 to 120% for the three matrices with relative standard deviation values lower than 20%. Limits of quantification of the method achieved were in the range 6–178 ng/L for all samples and analytes. The methodology was applied for the evaluation of real samples finding the presence of DMP, DPP, BBP, DIBP and DBP in some of the analysed matrices. [ABSTRACT FROM AUTHOR]

• Polyaniline-coated Fe3O4 m-NPs were synthesised and characterised in the laboratory. • An m-µ-dSPE protocol was developed for the extraction of plastic migrants in jellies. • UHPLC-MS/MS was used for the determination of target analytes. • Recovery values were in the range 70-124%, and LOQs between 10.56 and 17.06 ng/L. • BBP and DCHP were detected and DEHA was quantified in a group of 11 marketed samples. Magnetic nanoparticles of Fe 3 O 4 coated with polyaniline have been synthesised through chemical co-precipitation, and successfully characterised using different techniques such as FT-IR and X-ray diffraction. Such nanocomposite was applied as sorbent for a new magnetic micro-dispersive solid phase extraction procedure for the extraction of seven plastic migrants in jelly samples, followed by determination using ultra-high performance liquid chromatography-tandem mass spectrometry. Optimisation of several parameters that could affect extraction efficiency has been performed both by a conventional one-step-at-a-time approach and the use of a Box Behnken experimental design. The developed method was successfully validated obtaining recovery values in the range 70-124% with relative standard deviations lower than 20%, limits of quantification in the range 0.0106-0.0171 µg/L, and R2 values higher than 0.9915 for all the analytes. The greenness of the procedure was also evaluated using the AGREE calculator. Finally, the developed method was applied for the determination of plastic migrants in a group of 11 commercial jellies acquired in local stores. Results showed the presence of BBP in almost all the samples and DCHP in three of them, as well as DEHA, which was detected in another three commercial samples and quantified at a concentration of 2.17 µg/L in another one. [ABSTRACT FROM AUTHOR]

Abstract: In this manuscript, a new method based on the use of off-line dispersive solid-phase extraction (dSPE) combined with ultra-high performance liquid chromatography with diode-array detection was developed to determine 11 sulfonamide antibiotics (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine, sulfadimidin, sulfamethoxypyridazine, sulfadoxine, sulfamethoxazole, sulfisoxazole and sulfadimethoxine) in mineral waters with different mineral content. For this purpose, pristine multi-walled carbon nanotubes (MWCNTs) and magnetic-MWCNTs (m-MWCNTs) were used as sorbents. Magnetic nanoparticles were synthesized by means of a solvothermal process, assembled onto CNTs through an “aggregation wrap” mechanism and characterized by scanning electron microscopy. Parameters affecting the extraction such as volume and pH of the sample, amount of sorbent and type and volume of eluent were optimized. Once optimum extraction conditions (250mL of water at pH 6.0 and elution with 25mL of MeOH) were obtained, the extraction efficiency of the different carbon nanomaterials was compared. Results demonstrated the higher extraction capacity of pristine MWCNTs with recoveries between 61 and 110% (except for sulfacetamide which ranged between 40 and 53%) and between 22 and 77% for m-MWCNTs. Limits of detection lower than 32ng/L were achieved for all of the analyzed samples. [Copyright &y& Elsevier]

• Polypyrrole-coated Fe 3 O 4 m-NPs were prepared and characterised in the laboratory. • Fe 3 O 4 @PPy m-NPs were applied for the microextraction of PAEs from food and beverages. • The determination of target analytes was carried out by UHPLC-QqQ-MS/MS. • Recovery and LOQs were in the ranges 70-114% and 0.147-0.416 µg/L, respectively. • DAP and BBP were found in some of the real samples evaluated. Synthesised polypyrrole-coated Fe 3 O 4 magnetic nanoparticles have been successfully characterised and applied as sorbent for the magnetic-micro-dispersive solid-phase extraction of eleven phthalic acid esters from jelly and apple-based beverage matrices widely consumed by the population and, especially, by children. Sorbent was synthesised through chemical coprecipitation and subsequently characterised by different techniques. The influence of several parameters on the extraction efficiency was exhaustively evaluated using a step-by-step strategy. The separation and quantification of the selected phthalates were performed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. The validation of the methodology was carried out for jellies and apple-based beverages, employing dihexyl phthalate-3,4,5,6-d 4 as the surrogate standard. Relative recovery values were in the range 70–114% for both matrices and relative standard deviations below 20% were obtained. The limits of quantification of the method were found in the range 0.147–0.416 µg/L. Feasibility of the developed methodology was proved by the analysis of commercialised jelly and apple-based beverage products. [ABSTRACT FROM AUTHOR]