44 results on '"Wang, Hantao"'
Search Results
2. Metabolic Profiling of Varronia curassavica Jacq. Terpenoids by Flow Modulated Two-Dimensional Gas Chromatography Coupled to Mass Spectrometry
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Roselaine Facanali, Marcia Ortiz Mayo Marques, and Leandro Wang Hantao
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varronia curassavica ,essential oil ,seasonality ,gas chromatography (gc) ,comprehensive two-dimensional gas chromatography (gc×gc) ,flow-modulated ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In this study, a metabolomic approach was used to investigate the effect of seasonality on the chemical composition and yield of anti-inflammatory active principle, α-humulene, in the essential oil of three genotypes of Varronia curassavica Jacq. (Syn. Cordia verbenaceae). The essential oils were extracted by hydrodistillation and analyzed by comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS). The GC×GC approach a three-fold improvement in qualitative analysis (48 compounds were identified by GC-MS versus 135 by GC×GC-MS). The improved resolving power of GC×GC resolved important coelutions and enabled the detection of unusual substances in V. curassavica essential oil. The chromatographic data was analyzed by using peak table-based chemometrics, namely, principal component analysis (PCA) and hierarchical cluster analysis (HCA). The metabolic study showed that seasonality has a significant effect on the chemical composition. The α-humulene content was affected by genotype and season. Spring and summer were the best harvest seasons for the yield of the active ingredient, found in higher concentrations in the VC2 genotype. The proposed metabolomic workflow was successfully applied to terpene analysis found in V. curassavica essential oil, and such results have broadened our understanding of the influence of seasonal factors on the specialized metabolism of the species.
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- 2020
- Full Text
- View/download PDF
3. A Bottom-Up Approach for Data Mining in Bioaromatization of Beers Using Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry
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Andre Cunha Paiva, Daniel Simões Oliveira, and Leandro Wang Hantao
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foodomics ,brazilian yeast ,craft beer ,sensomics ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
In this study, we report the combination of comprehensive two-dimensional gas chromatography (GC×GC) with multivariate pattern recognition through template matching for the assignment of the contribution of Brazilian Ale 02 yeast strain to the aroma profile of beer compared with the traditional Nottingham yeast. Volatile organic compounds (VOC) from two beer samples, which were fermented with these yeast strains were sampled using headspace solid-phase microextraction (HS-SPME). The aroma profiles from both beer samples were obtained using GC×GC coupled to a fast scanning quadrupole mass spectrometer. Data processing performed through multiway principal components analysis succeeded in separating both beer samples based on yeast strain. The execution of a simple and reliable procedure succeeded and identified 46 compounds as relevant for sample classification. Furthermore, the bottom-up approach spotted compounds found exclusively in the beer sample fermented with the Brazilian yeast, highlighting the bioaromatization properties introduced to the aroma profile by this yeast strain.
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- 2019
- Full Text
- View/download PDF
4. Sample Preparation for Solid Petroleum-Based Matrices Based on Direct Matrix Introduction Oriented to Hydrocarbon Profiling
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Emanoel Nazareno Ramalho de Souza, Julián Eduardo Ballen Castiblanco, Felipe P. Fleming, Amilton Moreira de Oliveira, and Leandro Wang Hantao
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chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Matrix (mathematics) ,chemistry.chemical_compound ,Fuel Technology ,Hydrocarbon ,020401 chemical engineering ,Chemical engineering ,chemistry ,Petroleum ,Sample preparation ,0204 chemical engineering ,0210 nano-technology - Abstract
Multicomponent mixtures may be considered complex because of the overwhelming number of sample constituents and their broad range of physical–chemical properties. Such features translate into chall...
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- 2020
5. Consumable-free Comprehensive Three-Dimensional Gas Chromatography and PARAFAC for Determination of Allergens in Perfumes
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Ronei J. Poppi, Victor H. C. Ferreira, and Leandro Wang Hantao
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Resolution (mass spectrometry) ,010405 organic chemistry ,Chemistry ,business.industry ,010401 analytical chemistry ,Organic Chemistry ,Clinical Biochemistry ,Mass spectrometry ,01 natural sciences ,Biochemistry ,Consumer safety ,0104 chemical sciences ,Analytical Chemistry ,Gas chromatography ,Deconvolution ,Process engineering ,business - Abstract
A new consumable-free three-dimensional comprehensive gas chromatography (GC3-FID) was designed with modulators already known to comprehensive two-dimensional gas chromatography (GC × GC) users to showcase the opportunity of implementing GC3 systems. A hybrid interface composed of a thermal desorption modulator and a fast forward-flush differential flow modulator was used with modulation periods of 6 s and 300 ms, respectively. The determination of allergens in perfumes associated with chemometric tools, namely, parallel factor analysis (PARAFAC) was accomplished to demonstrate the validity of the proposed system. Evaluated allergens included already regulated ones in Brazil and Europe, such as geraniol and menthol, as well as potential allergens recommended in a 2011 opinion reported by the European Scientific Committee on Consumer Safety. Limits of detection were found to be suitable for current regulations, under 0.001% or 10 µL L−1 for leave-on products. Considerations on the required acquisition rates, the limitations imposed by current modulator technology, the modulation periods used, and how they affect all three dimensions are thoroughly discussed. A GC3 coupled with mass spectrometry (GC3-MS) approach is also covered, as well as a comparison of the signal resolution/deconvolution with the increase of data dimensionality. Lastly, the union of GC3 and chemometric tools allowed for a solution that may be used for both qualitative and quantitative analyses.
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- 2020
6. The Role of Gas Chromatography in Bioanalysis
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Nathália de Aguiar Porto and Leandro Wang Hantao
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Bioanalysis ,Chromatography ,Chemistry ,Gas chromatography - Published
- 2021
7. Profiling naphthenic acids in produced water using hollow fiber liquid-phase microextraction combined with gas chromatography coupled to Fourier transform Orbitrap mass spectrometry
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Nathália de Aguiar Porto, Juliana Crucello, Rogério M. Carvalho, Iris Medeiros Junior, Roselaine Facanali, and Leandro Wang Hantao
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Chemical ionization ,Chromatography ,Fourier Analysis ,Chemistry ,Liquid Phase Microextraction ,Organic Chemistry ,Carboxylic Acids ,Petroleomics ,Water ,General Medicine ,Orbitrap ,Mass spectrometry ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,Mass Spectrometry ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,law ,Sample preparation ,Gas chromatography ,Monoisotopic mass ,Derivatization - Abstract
In this study, we describe the development of an analytical method to profile naphthenic acids (NAs) from produced water (PW). The NAs were isolated by hollow fiber liquid-phase microextraction (HF-LPME). A microwave-assisted methylation method was used to convert the free acids into its corresponding naphthenic methyl esters (NAMEs). The best reaction conditions were ascertained using central composite design. The optimized sample preparation method exhibited an improved analytical eco-scale value (80 vs. 61) compared to conventional liquid-liquid extraction. Although the primary goal was qualitative analysis of NAMEs (e.g., group-type separation) in produced water, the quantitative performance was also evaluated for future investigations. The instrumental detection and quantification limits were 0.10 ng mL−1 and 0.16 ng mL−1, respectively, using full spectrum data acquisition. The accuracy and precision of the proposed method ranged from 90.4 to 96.6 % and 3.3 to 13.1 %, respectively, using matrix-matched working solutions (0.1, 0.5, and 1.0 µg mL−1). The monoisotopic masses of the adduct ions ([M+H]+) and its corresponding fine isotopic patterns were used to determine the elemental composition of the NAMEs in the PW samples. Qualitative analysis indicated the O2 class as the predominant class in all samples with carbon numbers ranging from C5 to C19 and double bond equivalent (DBE) values of 1 to 8. Additional classes of polar compounds, i.e., O3, O4 and nitrogen-containing classes, are reported for the first time by gas chromatography coupled to Fourier transform Orbitrap mass spectrometry and chemical ionization.
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- 2021
8. Polymeric ionic liquid open tubular capillary column for on-line in-tube SPME coupled with UHPLC-MS/MS to determine endocannabinoids in plasma samples
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Maria Eugênia Costa Queiroz, Leandro Wang Hantao, and Israel Donizeti de Souza
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Sorbent ,Polymers ,Capillary action ,Ionic Liquids ,02 engineering and technology ,Solid-phase microextraction ,01 natural sciences ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Tandem Mass Spectrometry ,Liquid chromatography–mass spectrometry ,Humans ,Environmental Chemistry ,Sample preparation ,Chromatography, High Pressure Liquid ,Solid Phase Microextraction ,Spectroscopy ,Chromatography ,Molecular Structure ,010401 analytical chemistry ,Extraction (chemistry) ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Linear range ,AMOSTRAGEM ,Ionic liquid ,0210 nano-technology ,Endocannabinoids - Abstract
This manuscript describes the development of wall-coated open tubular capillary column with polymeric ionic liquids (PILs) for on-line in-tube solid phase microextraction coupled with ultra high-performance liquid chromatography tandem mass spectrometry (in-tube SPME/UHPLC-MS/MS) to determine anandamide (AEA) and 2-arachidonoyl glycerol (2 A G) in plasma samples. Selective PILs were synthetized from the [VC6IM][Cl], [VC16IM][Br], and [(VIM)2C10]2 [Br] - ionic liquids - by in-situ thermal-initiated polymerization in a fused silica capillary column for in-tube SPME. The synthesis procedure was optimized, and the capillary columns were characterized using spectroscopic and chromatography techniques. The chemically bonded and cross-linked PIL-based sorbent phase (thickness coating: 1.7 μm) presented high chemical and mechanical stability. Among the sorbents evaluated, the PIL-based capillary, [VC16IM][Br]/[(VIM)2C10]2 [Br] presented the best performance with a sorption capacity of 37,311 ng cm−3 and 48,307 ng cm−3 for AEA and 2 A G, respectively. This capillary was reused more than ninety times without significant changes in extraction efficiency. The in-tube SPME-UHPLC-MS/MS method presented a linear range from 0.1 ng mL−1 to 100 ng mL−1 for AEA, and from 0.05 ng mL−1 to 100 ng mL−1 for 2 A G, with coefficients of determination higher than 0.99, p-value for Lack-of-fit test higher than 0.05 (α of 0.05), precision with coefficient of variation (CV) values ranging from 1.6 to 14.0% and accuracy with relative standard deviation (RSD) values from −19.6% to 13.2%. This method was successfully applied to determine AEA and 2 A G in plasma patients with Parkinson's disease. The concentrations in these plasma samples ranged from 0.14 to 0.46 ng mL−1 for AEA and from
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- 2019
9. Opportunities for green microextractions in comprehensive two-dimensional gas chromatography / mass spectrometry-based metabolomics – A review
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Fabio Augusto, Joao Raul Belinato, Fernanda Furlan Gonçalves Dias, Leandro Wang Hantao, and Jaqueline D. Caliman
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Bioanalysis ,Chemistry ,010401 analytical chemistry ,Ionic Liquids ,02 engineering and technology ,Research opportunities ,021001 nanoscience & nanotechnology ,Mass spectrometry ,01 natural sciences ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,0104 chemical sciences ,Analytical Chemistry ,Metabolomics ,Environmental Chemistry ,Extraction methods ,Sample preparation ,Biochemical engineering ,0210 nano-technology ,Solid Phase Microextraction ,Spectroscopy - Abstract
Microextractions have become an attractive class of techniques for metabolomics. The most popular technique is solid-phase microextraction that revolutionized the field of modern sample preparation in the early nineties. Ever since this milestone, microextractions have taken on many principles and formats comprising droplets, fibers, membranes, needles, and blades. Sampling devices may be customized to impart exhaustive or equilibrium-based characteristics to the extraction method. Equilibrium-based approaches may rely on additional methods for calibration, such as diffusion-based or on-fiber kinetic calibration to improve bioanalysis. In addition, microextraction-based methods may enable minimally invasive sampling protocols and measure the average free concentration of analytes in heterogeneous multiphasic biological systems. On-fiber derivatization has evidenced new opportunities for targeted and untargeted analysis in metabolomics. All these advantages have highlighted the potential of microextraction techniques for in vivo and on-site sampling and sample preparation, while many opportunities are still available for laboratory protocols. In this review, we outline and discuss some of the most recent applications using microextractions techniques for comprehensive two-dimensional gas chromatography-based metabolomics, including potential research opportunities.
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- 2018
10. Essential Oils of New Lippia alba Genotypes Analyzed by Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography (GC×GC) and Chemometric Analysis
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Roselaine Facanali, Leandro Wang Hantao, Marcia Ortiz Mayo Marques, Walter José Siqueira, Leila Gimenes, Júlio César Rodrigues Lopes Silva, Agronomic Institute, Universidade Estadual Paulista (Unesp), and Universidade Estadual de Campinas (UNICAMP)
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0106 biological sciences ,Genotype ,Acyclic Monoterpenes ,lemon balm ,Pharmaceutical Science ,Sabinene ,Mass spectrometry ,01 natural sciences ,Gas Chromatography-Mass Spectrometry ,Article ,Analytical Chemistry ,chemistry.chemical_compound ,QD241-441 ,Linalool ,Drug Discovery ,Myrtenol ,Oils, Volatile ,Plant Oils ,Food science ,Physical and Theoretical Chemistry ,Chemical composition ,essential oils ,Bicyclic Monoterpenes ,Lippia alba ,comprehensive two-dimensional gas chromatography ,biology ,Terpenes ,flow-modulated ,Verbenaceae ,010401 analytical chemistry ,Organic Chemistry ,biology.organism_classification ,0104 chemical sciences ,chemistry ,Chemistry (miscellaneous) ,Molecular Medicine ,Gas chromatography ,Lippia ,010606 plant biology & botany - Abstract
Made available in DSpace on 2021-06-25T10:29:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-16 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Lippia alba (Mill.) N. E. Br. (Verbenaceae) is an aromatic shrub whose essential oils have stood out as a promising source for application in several industrial fields. In this study, the essential oils chemical characterization of eight new L. alba genotypes was performed. The selected materials were collected from the Active Germplasm Bank of the Agronomic Institute and the essential oils were extracted by hydrodistillation. Flow-modulated comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) was employed for chemical characterization and evaluation of possible co-eluted compounds. In addition, the chemical analyses were submitted to multivariate statistical analyses. From this investigation, 73 metabolites were identified in the essential oils of the genotypes, from which α-pinene, β-myrcene, 1,8-cineole, linalool, neral, geranial, and caryophyllene oxide were the most abundant compounds among the accessions. This is the first report disclosing α-pinene in higher amounts in L. alba (19.69%). In addition, sabinene, trans-verbenol, myrtenol, (E)-caryophyllene, α-guaiene, germacrene D, and α-bulnesene were also found in relevant quantities in some of the genotypes, and myrtenal and myrtenol could be well separated through the second dimension. Such results contributed to the understanding of the chemical composition of those new genotypes, being important to drive a future industrial applicability and studies in genetic breeding. Vegetable Genetic Resources Center Agronomic Institute School of Agriculture São Paulo State University (Unesp) Institute of Chemistry University of Campinas (Unicamp) School of Agriculture São Paulo State University (Unesp) FAPESP: 2018/26066-1
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- 2021
11. Practical Considerations in Method Development for Gas Chromatography-Based Metabolomic Profiling
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Andre Cunha Paiva, Roselaine Facanali, Leandro Wang Hantao, Juliana Crucello, and Amilton Moreira de Oliveira
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Profiling (computer programming) ,Analyte ,Resolution (mass spectrometry) ,business.industry ,Computer science ,chemistry.chemical_compound ,Metabolomics ,chemistry ,Sample preparation ,Gas chromatography ,Process engineering ,business ,Derivatization ,Selection (genetic algorithm) - Abstract
This chapter discusses the fundamentals of gas chromatography (GC) to improve method development for metabolic profiling of complex biological samples. The selection of column geometry and phase ratio impacts analyte mass transfer, which must be carefully optimized for fast analysis. Stationary phase selection is critical to obtain baseline resolution of critical pairs, but such selection must consider important aspects of metabolomic protocols, such as derivatization and dependence of analyte identification on existing databases. Sample preparation methods are also addressed depending on the sample matrix, including liquid-liquid extraction and solid-phase microextraction.
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- 2021
12. Improving selective channel occlusion of complex hydrocarbons and fatty acid methyl esters in urea crystals by using an expendable 3D-printed microfluidic device for sample preparation in untargeted petroleomics
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Reverson Fernandes Quero, Dosil Pereira de Jesus, Julián Eduardo Ballen Castiblanco, Leandro Wang Hantao, and Amilton Moreira de Oliveira
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Heptadecane ,Chromatography ,010401 analytical chemistry ,Microfluidics ,Tridecane ,Petroleomics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Petrochemical ,chemistry ,Principal component analysis ,Miniaturization ,Environmental Chemistry ,Sample preparation ,0210 nano-technology ,Spectroscopy - Abstract
In this study, we describe a proof-of-concept investigation of the potential and limitations of employing channel occlusion for sample preparation in untargeted analysis in petroleomics. A middle petroleum distillate composed of fatty acid methyl esters (FAME) and a complex mixture of linear, branched, and cyclic hydrocarbons were selected as the model samples for this investigation. A microfluidic device was engineered to overcome the limitations of channel occlusion, resulting in a quick and robust method for sample preparation. The 3D-printed device using fused deposition modelling (FDM) allowed the combination of a 13-h multi-step sample handling protocol into a 2-min single-step procedure, which is also automation-friendly. Such developments were also evaluated using the analytical eco-scale to guide the development of a green analytical method. The relative standard deviation decreased 2-fold with method miniaturization. The efficiency of n-alkane removal was extended from tridecane (n-C13) to heptadecane (n-C17), compared to original method (n-C16 to n-C17). The analytical performance of the method was investigated for untargeted analysis. The tool used to probe the intra- and inter-class variance was multi-way principal component analysis (MPCA). MPCA modelling revealed that both methods generated equivalent chemical information, highlighting the benefits of reliable and reproducible sample preparation methods, especially for untargeted analysis. Such awareness is critical to avoid the generation of misleading results in fields that heavily rely on untargeted analysis and fingerprinting, such as petroleomics.
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- 2020
13. Chemical diversity of essential oils from the Brazilian medicinal plant Lychnophora pinaster Mart from different environments
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João Semir, Maria da Paz Lima, Marcia Ortiz Mayo Marques, Ernane Ronie Martins, Leandro Wang Hantao, Alexandra Christine Helena Frankland Sawaya, Maria Imaculada Zucchi, Filipe Pereira Giardini Bonfim, Ana Paula da Silva Marques, Dayane Graziella Pereira de Oliveira dos Santos, Universidade Estadual Paulista (Unesp), Universidade Estadual de Campinas (UNICAMP), Universidade Federal de Minas Gerais (UFMG), Agencia Paulista Tecnol Agronegocios, and Inst Agron Estado Sao Paulo
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0106 biological sciences ,Chemotypes ,Population ,Endangered species ,Biology ,Sesquiterpene ,01 natural sciences ,law.invention ,chemistry.chemical_compound ,Phytomedicine ,Nutrient ,law ,Botany ,Native populations ,education ,Chemical composition ,Essential oil ,education.field_of_study ,010405 organic chemistry ,0104 chemical sciences ,chemistry ,Arnica-mineira ,Soil water ,Agronomy and Crop Science ,Sesquiterpenes ,010606 plant biology & botany - Abstract
Made available in DSpace on 2021-06-25T12:24:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Lychnophora pinaster Mart. (arnica-mineira) is an endangered popular Brazilian medicinal species with occurrence restricted to the State of Minas Gerais, Brazil. The species inhabits areas with different soil and climate conditions, which may affect the chemical composition of essential oils. The plant is frequently cited for its anti-rheumatic, anti-inflammatory, analgesic and other biological activities. Previous works in a restricted area report a predominance of phenylpropanoids compounds in its essential oil composition. Due to the potential economic use as a phytomedicine and the limited geographic coverage of previous studies, this research aimed to analyze the essential oil of populations from different regions and the influence of the soil on the essential oil chemical composition. Six populations of two regions were analyzed: Diamantina (DIMa), Olhos D'Agua (OD) and Grao Mogol (GM), from the North, and Caete/Rio Acima (CTRA), Nova Lima/Serra da Calcada (NLSC) and Serra da Moeda (SM), from the Metropolitan Region of Belo Horizonte. Soil analyses revealed differences between the soils. Diamantina (DIMa) and Serra da Moeda (SM) presented the highest essential oil yield among populations (0.12 %), while the smallest was observed for NLSC, with 0.04 %. There was no difference in yield between regions. Principal component analysis demonstrated the diversity of chemical profiles between populations. For the northern region, the major substances were alpha-pinene (12 %) for GM; 14-acetoxy a hu mulene, (21.9 %) for DIMa and 14-hydroxy-4,5-dehydro-caryophyllene and squamulose (9.13 % and 8.30 %, respectively) for OD. For the metropolitan region of Belo Horizonte, the substances with higher levels were sesquiterpene 1 (35.16 %) and sesquiterpene 7 (8.13 %) for MS; 1,7-diepi-a-cedrenal (6.46 %), (Z)-nerolidol (12.60 %), sesquiterpene 2 (14.62 %) in CTRA. Olhos D'Agua (OD) registered as the major an unidentified compound (38.46 %). Diamantina, Olhos D'Agua and Nova Lima/Serra da Calcada showed chemical similarity, although they belong to different regions of the state, distant by 273 km. Grao Mogol (GM), Serra da Moeda (SM) and Caete/Rio Acima (CTRA) did not show chemical similarity to each other or to the others. The populations differed for the chemical composition and soil characteristics. The multivariate analysis indicated that certain compounds and nutrients of the soil were simultaneously relevant for population differentiation. The chemical diversity found in L. pinaster essential oils of different regions with predominance of sesquiterpenes may affect the biological activities. Univ Estadual Paulista, Inst Biociencias, Dept Bot, Rua Prof Dr Antonio Celso Wagner Zanin 250, BR-18618689 Botucatu, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agron, Dept Horticultura, Rua Jose Barbosa de Barros 1780, BR-18610307 Botucatu, SP, Brazil Univ Estadual Campinas, Inst Nacl Pesquisas Amazonia, Ctr Inovacao Tecnol, Ave Andre Araujo 2936,Caixa Postal 478, BR-69050001 Manaus, Amazonas, Brazil Univ Estadual Campinas, Inst Biol, Dept Bot, Rua Monteiro Lobato 255,Caixa Postal 6109, BR-13083862 Campinas, SP, Brazil Univ Fed Minas Gerais, Inst Ciencias Agr, Av Univ 1000, BR-39404547 Montes Claros, MG, Brazil Agencia Paulista Tecnol Agronegocios, Polo Reg Desenvolvimento Tecnol Ctr Sul, Caixa Postal 28, BR-13400970 Piracicaba, SP, Brazil Univ Estadual Campinas, Inst Quim, Dept Quim Analit, Rua Monteiro Lobato 270, BR-13083970 Campinas, SP, Brazil Univ Estadual Campinas, Fac Ciencias Farmaceut, Rua Candid Portinari,200,Cidade Univ, BR-13083871 Campinas, SP, Brazil Inst Agron Estado Sao Paulo, Ctr Pesquisa Recursos Genet Vegetais, Ave Barao de Itapura 1481, BR-13020902 Campinas, SP, Brazil Univ Estadual Paulista, Inst Biociencias, Dept Bot, Rua Prof Dr Antonio Celso Wagner Zanin 250, BR-18618689 Botucatu, SP, Brazil Univ Estadual Paulista, Fac Ciencias Agron, Dept Horticultura, Rua Jose Barbosa de Barros 1780, BR-18610307 Botucatu, SP, Brazil FAPESP: 2017/24927-7 CNPq: 309957/2015-0 CAPES: 001
- Published
- 2020
14. Drinking water nitrosamines in a large metropolitan region in Brazil
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Cassiana Carolina Montagner, Beatriz De Caroli Vizioli, and Leandro Wang Hantao
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Detection limit ,Health, Toxicology and Mutagenesis ,Extraction (chemistry) ,General Medicine ,010501 environmental sciences ,01 natural sciences ,Pollution ,chemistry.chemical_compound ,chemistry ,Nitrosamine ,Environmental chemistry ,visual_art ,Ultrapure water ,visual_art.visual_art_medium ,Environmental Chemistry ,Ecotoxicology ,Environmental science ,Gas chromatography ,Solid phase extraction ,Charcoal ,0105 earth and related environmental sciences - Abstract
Nitrosamines are a concerning group of carcinogens, which have gained increasing attention over the last years, frequently found in drinking and recycled water systems. In this work, an analytical method was developed for the detection and quantification of seven nitrosamines (NDMA, NMEA, NPYR, NDEA, NPIP, NDPA, and NDBA) in drinking water. The method is based on gas chromatography coupled with a single quadrupole mass spectrometer (GC-MS) with electron ionization (EI) mode. Sample enrichment and matrix cleanup by solid-phase extraction (SPE) were performed using the US EPA Method 521 cartridge packed with coconut-based charcoal. The simple method allowed reliable identification and quantification of nitrosamines in the water at nanogram per liter levels. The optimized method was validated at three concentration levels (20, 100, and 200 ng L-1) in ultrapure and drinking water samples. Average recoveries were 63-87% for ultrapure water and 38-79% for drinking water with relative standard deviations (RSD) below 10% for both matrices. Method detection limits were 1.23-3.14 ng L-1. The described method was applied to eighteen drinking water samples collected from 13 cities of the Metropolitan Region of Campinas (Sao Paulo, Brazil). NDMA was the most frequent nitrosamine detected (89% of samples) and had the highest concentration level found (67 ng L-1). The levels of nitrosamines found in drinking water samples are of considerable relevance since the selected area is a major urban center that has amply expanded industrial and agricultural activities over the last few decades. To the best of our knowledge, this is the first evaluation of nitrosamines in drinking water conducted in Brazil to date.
- Published
- 2020
15. Exploring a public database to evaluate consumer preference and aroma profile of lager beers by comprehensive two-dimensional gas chromatography and partial least squares regression discriminant analysis
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Andre Cunha Paiva and Leandro Wang Hantao
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Chromatography ,biology ,Chemistry ,010401 analytical chemistry ,Organic Chemistry ,Orthogonal signal correction ,General Medicine ,010402 general chemistry ,biology.organism_classification ,Solid-phase microextraction ,Linear discriminant analysis ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,Metadata ,Foodomics ,Partial least squares regression ,Gas chromatography ,Aroma - Abstract
In this paper is reported a proof of concept study to evaluate the usage of a public metadata base about beers to guide chemical interpretation of volatile organic compounds (VOC) profiling. 1,569,641 consumers’ evaluations were collected from Untappd® platform and used to define a property of interest according to beer preference. 14 brands of beers from lager family were divided in two groups, first one containing samples with low consumers’ ratings and the second with brands that exhibited high evaluations. VOC profiles were extracted by headspace solid phase microextraction (HS-SPME) and analyzed using comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC × GC-MS). To correlate the VOC profile and consumers’ preference, unfolded-partial least squares discriminant analysis (U-PLS-DA) with orthogonal signal correction (OSC) were employed. The mathematical model successfully classified all the beer samples. Furthermore, a template match protocol identified 31 compounds related to consumers’ preference. This proof of concept paper revealed the potential usage of public metadata bases for comprehensive chemical interpretation of VOC profiling in foodomics.
- Published
- 2020
16. Use of color based chromatographic images obtained from comprehensive two-dimensional gas chromatography in authentication analyses
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Ronei J. Poppi, Victor H. C. Ferreira, and Leandro Wang Hantao
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Volatile Organic Compounds ,Authentication ,Chromatography, Gas ,Chromatography ,Software ,Chemistry ,business.industry ,Image processing ,business ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry - Abstract
Comprehensive two-dimensional gas chromatography (GC×GC) has been an important technique used to acquire as much information as possible from a wide variety of samples. Qualitative contour plots analysis provides useful information and in daily use it ends up being handled as images of the volatile organic compounds by analysts. Cachaça samples are used in this paper to showcase the use of two-dimensional chromatographic images as the main source for authentication purposes through one-class classifiers, such as data-driven soft independent modeling of class analogy (DD-SIMCA). The proposed workflow summarizes this fast and easy process, which can be used to certify a specific brand in comparison to other brands, as well as to authenticate if samples have been adulterated. Lower quality cachaças, non-aged cachaças and cachaças aged in different wooden barrels were tested as adulterants. Chromatographic images allowed for the distinction of all brands and nearly every adulteration tested. Sensitivity was estimated at 100% for all models and specificity ranged from 96% to 100%. Different approaches were used, alternating from working with whole-sized images to working with smaller resized versions of those images. Resized chromatographic images could be potentially useful to easily compensate for slight chromatographic misalignments, allowing for faster calculations and the use of simpler software. Reductions to 50% and 25% of the original size were tested and the results did not greatly differ from whole images model. As such, 2D chromatographic images have been found to be an interesting form of evaluating a product's authenticity.
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- 2021
17. Fundamentals of and recent advances in sorbent-based headspace extractions
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Andre Cunha Paiva, Juliana Crucello, Nathália de Aguiar Porto, and Leandro Wang Hantao
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Bioanalysis ,Sorbent ,Chromatography ,Materials science ,Nanostructured materials ,010401 analytical chemistry ,01 natural sciences ,Method development ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Sample preparation ,Gas chromatography ,Derivatization ,Spectroscopy - Abstract
In this review, we present the most significant developments since 2013 of sorbent-based headspace extractions that resonated with the latest guidelines of green analytical chemistry. The fundamentals of each technique are discussed, as well as representative applications in the environmental, food analysis, and bioanalysis fields. Such equilibrium-based extractions are currently embodied by solid-phase microextraction (SPME) devices (e.g., fiber-based, TF-SPME, SPME Arrow), needle-based devices (e.g., SPDE, ITEX, NTD), and coated stir bars (e.g., HSSE, SBSE). This review covers most aspects of sample preparation, including theory, fundamental developments, novel sorbent phases (e.g., metal organic frameworks (MOF), carbon-based nanostructured materials, and ionic liquids (IL)), derivatization for gas chromatography (GC), and method development (e.g., design of experiments). In particular, vacuum-assisted extractions have been highlighted due to their recent developments.
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- 2021
18. Simple, Expendable, 3D-Printed Microfluidic Systems for Sample Preparation of Petroleum
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Fabio Augusto, Ronei J. Poppi, Rogério M. Carvalho, Angelo L. Gobbi, Marcos N. Eberlin, Érica M. Kataoka, Jandyson M. Santos, Leandro Wang Hantao, and Rui Cesar Murer
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3d printed ,Chromatography ,Fused deposition modeling ,010401 analytical chemistry ,Extraction (chemistry) ,Microfluidics ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,Solvent ,chemistry.chemical_compound ,chemistry ,law ,Emulsion ,Petroleum ,Sample preparation ,0210 nano-technology - Abstract
In this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. This platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration using proposed approach. This 3D-printed μSPE device was applied to challenging matrices in oil and gas industry, such as crude oil and oil-brine emulsions. Case studies investigated important limitations of nonsilicon and nonglass microchips, namely, resistance to nonpolar solvents and conservation of sample integrity. Microfluidic features remained fully functional even after prolonged exposure to nonpolar solvents (20 min). Also, 3D-printed μSPE devices enabled fast emulsion breaking and solvent deasphalting of petroleum, yielding high recovery values (98%) without compromising maltene integrity. Such finding was ascertained by high-resolution molecular analyses using comprehensive two-dimensional gas chromatography and gas chromatography/mass spectrometry by monitoring important biomarker classes, such as C
- Published
- 2017
19. Acrylamide mitigation in French fries using native l-asparaginase from Aspergillus oryzae CCT 3940
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Fernanda Furlan Gonçalves Dias, Stanislau Bogusz Junior, Hélia Harumi Sato, Fabio Augusto, and Leandro Wang Hantao
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0106 biological sciences ,Asparaginase ,biology ,French fries ,food and beverages ,04 agricultural and veterinary sciences ,biology.organism_classification ,040401 food science ,01 natural sciences ,Glutaminase activity ,Maillard reaction ,symbols.namesake ,chemistry.chemical_compound ,0404 agricultural biotechnology ,chemistry ,Aspergillus oryzae ,010608 biotechnology ,Acrylamide ,Aspartic acid ,symbols ,Asparagine ,Food science ,ALIMENTAÇÃO ,Food Science - Abstract
The Maillard reaction is responsible for color and flavor formation in fried, roasted and baked foods. However, this reaction can also promote the formation of acrylamide, a potential human carcinogen. The application of l -asparaginase represents a promising method for acrylamide mitigation in heated products by the direct conversion of the precursor l -asparagine to l -aspartic acid and ammonia, which does not lead to additional acrylamide formation. Our research group produced and purified an l -asparaginase from native Aspergillus oryzae CCT 3940 with highly potential for acrylamide mitigation. To verify the enzymatic effectiveness, we compared the native l -asparaginase with the commercial recombinant enzyme. For this purpose, a GC-MS/MS method was developed, optimized and validated for the assessment of acrylamide in French fries. Our results indicate a relationship between the l -asparagine content and acrylamide formation in French fries. The acrylamide concentration of the fried potato treated with the l -asparaginase from A. oryzae CCT 3940 and treated with commercial enzyme reduced 72% and 92%, respectively compared to control sample. Moreover, the l -asparaginase from A. oryzae CCT 3940 showed no l -glutaminase activity, while commercial enzyme promoted a decrease in the l -glutamine content (25%). Our results suggest that l -asparaginase from A. oryzae CCT 3940 may be of great value for acrylamide mitigation.
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- 2017
20. Thermal desorption modulation for comprehensive two-dimensional gas chromatography using a simple and inexpensive segmented-loop fluidic interface
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Vanessa Mucédola, Leandro Wang Hantao, Luis C. S. Vieira, Angelo L. Gobbi, Ronei J. Poppi, and Danilo Pierone
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Analyte ,Chromatography ,Chemistry ,010401 analytical chemistry ,Thermal desorption ,Phase (waves) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Power (physics) ,Modulation ,Two-dimensional gas ,Fluidics ,0210 nano-technology ,Joule heating - Abstract
In this study, we introduce a modulation strategy for comprehensive two-dimensional gas chromatography (GC×GC) by using a simple and consumable-free modulator. This “Do-It-Yourself” interface comprised a 1.0 m×0.25 mm segment of MTX-5 metallic column and a low-cost DC power supply. Thermal desorption modulation (TDM) was attained using a dual-stage heater-based modulator in a novel segmented-loop configuration. TDM was achieved by alternating analyte trapping and thermal desorption. Former process relied on analyte partition to sorbent phase, while latter explored direct resistive heating. Introduction of an intermediate delay segment between the two stages mitigated analyte breakthrough, improving peak symmetry and chromatographic efficiency. This feature was critical to acquire reliable GC×GC modulation using such simple heater-based device. The effects of important modulation variables on 2D separations were investigated, including TDM stage length, dimension of delay loop, and outlet pressure. Significant advances and limitations of proposed TDM strategy were carefully determined. Proposed GC×GC prototype by using an in-oven TDM modulator was successfully applied to a series of challenging matrices, including petroleum distillates, biodiesel, and essential oil. This open-hardware, cost-effective modulator was easy to install and operate, as it circumvented the need for sophisticated components (e.g. moving parts and cooling systems). Therefore, our modulator is a compelling alternative to existing GC×GC solutions to operate in resource-limited laboratories.
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- 2017
21. Corrigendum to 'Opportunities for green microextractions in comprehensive two-dimensional gas chromatography / mass spectrometry-based metabolomics – A review' [Analytica Chimica Acta 1040 2018 1–18]
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Leandro Wang Hantao, Fernanda Furlan Gonçalves Dias, Joao Raul Belinato, Fabio Augusto, and Jaqueline D. Caliman
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Chromatography ,Chemistry ,010401 analytical chemistry ,Analytica ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Mass spectrometry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Analytical Chemistry ,Metabolomics ,Environmental Chemistry ,0210 nano-technology ,computer ,Spectroscopy ,computer.programming_language - Abstract
The purpose of this corrigendum is to present the correct silyl-acceptor reactivity order.
- Published
- 2020
22. A Bottom-Up Approach for Data Mining in Bioaromatization of Beers Using Flow-Modulated Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry
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Daniel Simoes Oliveira, Andre Cunha Paiva, and Leandro Wang Hantao
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Filtration and Separation ,Mass spectrometry ,01 natural sciences ,Analytical Chemistry ,lcsh:Chemistry ,foodomics ,Brazilian yeast ,sensomics ,Quadrupole mass analyzer ,Aroma ,Chromatography ,biology ,010405 organic chemistry ,Chemistry ,010401 analytical chemistry ,food and beverages ,Yeast strain ,biology.organism_classification ,lcsh:QC1-999 ,Yeast ,0104 chemical sciences ,lcsh:QD1-999 ,craft beer ,Principal component analysis ,Fermentation ,Gas chromatography ,lcsh:Physics - Abstract
In this study, we report the combination of comprehensive two-dimensional gas chromatography (GC×, GC) with multivariate pattern recognition through template matching for the assignment of the contribution of Brazilian Ale 02 yeast strain to the aroma profile of beer compared with the traditional Nottingham yeast. Volatile organic compounds (VOC) from two beer samples, which were fermented with these yeast strains were sampled using headspace solid-phase microextraction (HS-SPME). The aroma profiles from both beer samples were obtained using GC×, GC coupled to a fast scanning quadrupole mass spectrometer. Data processing performed through multiway principal components analysis succeeded in separating both beer samples based on yeast strain. The execution of a simple and reliable procedure succeeded and identified 46 compounds as relevant for sample classification. Furthermore, the bottom-up approach spotted compounds found exclusively in the beer sample fermented with the Brazilian yeast, highlighting the bioaromatization properties introduced to the aroma profile by this yeast strain.
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- 2019
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23. Simple and cost-effective determination of polychlorinated biphenyls in insulating oils using an ionic liquid-based stationary phase and flow modulated comprehensive two-dimensional gas chromatography with electron capture detection
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Juliana Crucello, Leandro Wang Hantao, and Danilo Pierone
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Chromatography ,Chromatography, Gas ,Chemistry ,Electron capture ,Elution ,Dodecane ,010401 analytical chemistry ,Organic Chemistry ,Reproducibility of Results ,General Medicine ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Polychlorinated Biphenyls ,0104 chemical sciences ,Analytical Chemistry ,Electron capture detector ,chemistry.chemical_compound ,Ionic liquid ,Two-dimensional gas ,Sample preparation ,Gas chromatography ,Oils - Abstract
In this article we describe a method using flow-modulated comprehensive two-dimensional gas chromatography with electron capture detector (FM–GC×GC–ECD) for the determination of polychlorinated biphenyls (PCBs) in complex transformer oils bypassing the need for sample preparation. A two-fold improvement in method development was attained. First, the solvation parameter model (SPM) was used to guide column selection. A highly cohesive ionic liquid-based phase (low l system constant), namely 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethanesulfonyl)imide, was used in the primary stage leading to negligible retention of interfering aliphatic hydrocarbons, which are eluted in the first upper quadrant of the chromatogram. The resulting separation space was used to resolve the critical class of compounds, namely, PCBs and polyaromatic hydrocarbons. Second, a unique combination of column geometries and phase ratios enabled highly efficient reverse fill/flush flow modulation using very low pressure for auxiliary gas flow. The proof of concept method described herein exhibited linearities ranging from 0.990 to 0.994, limits of quantitation (LOQ) from 2.23 and 6.85 µg mL−1, precision below 5% relative standard deviation (RSD), and accuracy from 84.2% to 108.9% showcasing the potential of FM–GC×GC for routine analysis.
- Published
- 2019
24. Optimization of serum sample preparation aiming at metabolomics analysis by comprehensive two-dimensional gas chromatography coupled to mass spectrometry
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Leandro Wang Hantao, Henrique Caracho Ribeiro, Isabella Brito Savieto, Andre Cunha Paiva, and Alessandra Sussulini
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chemistry.chemical_compound ,Metabolomics ,Chromatography ,Chemistry ,Two-dimensional gas ,Sample preparation ,General Medicine ,Gas chromatography ,Mass spectrometry ,Serum samples ,Derivatization - Abstract
This work has the purpose of optimizing the analysis of serum samples by comprehensive two-dimensional gas chromatography coupled to mass spectrometry, using derivatization for sample preparation, and aiming at further application in metabolomics studies of bipolar disorder.
- Published
- 2019
25. Simple Solid-Phase Extraction Method for High Efficiency and Low-Cost Crude Oil Demulsification
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Ronei J. Poppi, Karen M. Higa, Mariana Baptistão, Renato S. Lima, Augusto Guilhen, Leandro Wang Hantao, Luis C. S. Vieira, Rogério M. Carvalho, and Angelo L. Gobbi
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Chromatography ,General Chemical Engineering ,010401 analytical chemistry ,Aqueous two-phase system ,Energy Engineering and Power Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Dewatering ,Chloride ,0104 chemical sciences ,chemistry.chemical_compound ,Fuel Technology ,Adsorption ,Brine ,chemistry ,Emulsion ,medicine ,Petroleum ,Solid phase extraction ,0210 nano-technology ,medicine.drug - Abstract
A novel and simple method for petroleum emulsion breaking and desalting is described and applied to crude oil. Such complex samples consist of stable water–oil emulsions. The oil phase is comprised of petroleum whereas the aqueous phase is composed of brine, including seawater, with varying salt content. Herein, crude oil dewatering was performed by applying a small aliquot of sample to a supported-liquid extraction cartridge. Multiphasic equilibration allowed the aqueous phase to adsorb onto the surface of porous diatomaceous earth (e.g., Celite). Organic solvents such as n-heptane, methylene chloride, and toluene easily desorbed the remaining oil phase. Potentiometric Karl Fisher titration and conductivity analysis confirmed near exhaustive (>98%) water and salt removal alongside particulate matter. This phenomenon was strikingly observed in both mild and harsh salt content conditions with concentrations ranging from zero to 200 000 ppm; the latter is found in Brazilian presalt crude oil samples. Quanti...
- Published
- 2016
26. Characterization of the aroma profile of novel Brazilian wines by solid-phase microextraction using polymeric ionic liquid sorbent coatings
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Victor H. C. Ferreira, Patricia Ritschel, Ronei J. Poppi, Juliana Crucello, Leandro Wang Hantao, Marcia O. M. Marques, Jared L. Anderson, He Nan, Luiz Felipe Otavio Miron, Mauro Celso Zanus, Juliana Crucello, Institute of Chemistry, Universidade Estadual de Campinas, 270 Monteiro Lobato, Campinas, SP 13083-970, Brazil, Luiz F. O. Miron, Institute of Chemistry, Universidade Estadual de Campinas, 270 Monteiro Lobato, Campinas, SP 13083-970, Brazil, Victor H. C. Ferreira, Institute of Chemistry, Universidade Estadual de Campinas, 270 Monteiro Lobato, Campinas, SP 13083-970, Brazil, He Nan, Department of Chemistry, Iowa State University, Ames, IA 50011, USA, Marcia O. M. Marques, Agronomic Institute of Campinas, Campinas, SP 13012-970, Brazil, PATRICIA SILVA RITSCHEL, CNPUV, MAURO CELSO ZANUS, CNPUV, Jared L. Anderson, Department of Chemistry, Iowa State University, Ames, IA 50011, USA, Ronei J. Poppi, National Institute of Science and Technology in Bioanalytics (INCTBio), Campinas, SP 13083-970, Brazil, and Leandro W. Hantao, Institute of Chemistry, Universidade Estadual de Campinas, 270 Monteiro Lobato, Campinas, SP 13083-970, Brazil.
- Subjects
Sorbent ,Polymers ,Foodomics ,Ionic Liquids ,Wine ,02 engineering and technology ,Solid-phase microextraction ,01 natural sciences ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,Sensomics ,chemistry.chemical_compound ,Flavor and aroma ,Food chemistry ,Aroma ,Solid Phase Microextraction ,Chromatography ,biology ,Chemistry ,010401 analytical chemistry ,Extraction (chemistry) ,Discriminant Analysis ,021001 nanoscience & nanotechnology ,Divinylbenzene ,biology.organism_classification ,0104 chemical sciences ,Ionic liquid ,Odorants ,Gas chromatography–mass spectrometry ,0210 nano-technology ,Brazil ,Biomarkers - Abstract
In this study, a series of polymeric ionic liquid (PIL) sorbent coatings is evaluated for the extraction of polar volatile organic compounds (VOCs) from Brazilian wines using headspace solid-phase microextraction (HS-SPME), including samples from ?Isabella? and ?BRS Magna? cultivars?the latter was recently introduced by the Brazilian Agricultural Research Corporation ? National Grape & Wine Research Center. In this study, a series of polymeric ionic liquid (PIL) sorbent coatings is evaluated for the extraction of polar volatile organic compounds (VOCs) from Brazilian wines using headspace solid-phase microextraction (HS-SPME), including samples from ?Isabella? and ?BRS Magna? cultivars?the latter was recently introduced by the Brazilian Agricultural Research Corporation ? National Grape & Wine Research Center. The structurally tuned SPME coatings were compared to the commercial SPME phases, namely poly(acrylate) (PA) and divinylbenzene/carboxen/poly(dimethylsiloxane) (DVB/CAR/PDMS). The separation, detection and identification of the aroma profileswere obtained using comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS). The best performing PIL-based SPME fiber, namely 1-hexadecyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide with 1,12-di(3-vinylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide incorporated cross-linker supported on an elastic nitinol wire, exhibited superior performance to DVB/CAR/PDMS regarding the average number of extracted peaks and extracted more polar analytes providing additional insight into the aroma profile of ?BRS Magna? wines. Four batches of wine were evaluated, namely ?Isabella? and ?BRS Magna? vintages 2015 and 2016, using highly selective PIL-based SPME coatings and enabled the detection of 350+ peaks. Furthermore, this is the first report evaluating the aroma of ?BRS Magna? wines. A hybrid approach that combined pixel-based Fisher ratio and peak table-based data comparison was used for data handling. This proof-of-concept experiment provided reliable and statistically valid distinction of wines that may guide regulation agencies to create high sample throughput protocols to screen wines exported by Brazilian vintners. Made available in DSpace on 2019-05-01T00:44:24Z (GMT). No. of bitstreams: 1 Crucelloetal2018AnalyticalandBioanalyticalChemistry.pdf: 1957393 bytes, checksum: d44c912271d094147ccc347b257e6d8e (MD5) Previous issue date: 2018
- Published
- 2018
27. Intake of jaboticaba peel attenuates oxidative stress in tissues and reduces circulating saturated lipids of rats with high-fat diet-induced obesity
- Author
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Mário Roberto Maróstica, Leandro Wang Hantao, Anderson Luiz-Ferreira, Fabio Augusto, Marcelo Alexandre Prado, Stanislau Bogusz, Sabrina Alves Lenquiste, Juliana Kelly da Silva, Cinthia Baú Betim Cazarin, Ângela Giovana Batista, and Renato Nunes de Souza
- Subjects
Antioxidant ,medicine.medical_treatment ,Cyanidin ,Lipid peroxidation ,Fatty acids methyl esters ,Blood lipids ,Medicine (miscellaneous) ,medicine.disease_cause ,chemistry.chemical_compound ,medicine ,TX341-641 ,Food science ,Gallic acid ,Obesity ,Myrciaria jaboticaba (Vell.) Berg ,Nutrition and Dietetics ,Nutrition. Foods and food supply ,Polyphenols ,Antioxidant defenses ,chemistry ,Biochemistry ,Quercetin ,Oxidative stress ,Ellagic acid ,Food Science - Abstract
The bioactive compounds of freeze-dried jaboticaba peel (FJP), serum lipids and the antioxidant status of rats fed high-fat diets containing different doses of FJP were evaluated. Obesity was induced and three groups of the obese animals received high-fat diet with 1%, 2% and 4% FJP added (J1, J2 and J4, respectively). The HPLC–DAD analyses of the polyphenols in the FJP showed four compounds: gallic acid, cyanidin 3-glucoside, ellagic acid, and quercetin. The serum saturated fatty acids were reduced in J1 and J4-fed animals. The antioxidant defenses of plasma were increased in the J2 and J4-fed animals. All the FJP diets prevented lipid peroxidation in the liver and increased its antioxidant defenses. Lipid peroxidation in brain decreased with an increasing FJP content in the diet. The antioxidant status of the kidneys of J2 and J4-fed animals increased. Thus, FJP could be an alternative to minimize the high-fat diet-induced oxidative stress and circulating saturated lipids.
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- 2014
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28. Ionic Liquids in Analytical Chemistry: Fundamentals, Advances, and Perspectives
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Jared L. Anderson, Tien D. Ho, Leandro Wang Hantao, and Cheng Zhang
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chemistry.chemical_compound ,Chemistry ,Metal ions in aqueous solution ,Ionic liquid ,Nanotechnology ,Analytical Chemistry (journal) ,Analytical Chemistry - Abstract
265 Application of IL-DLLME in the Analysis of Pharmaceutical Entities 265 IL-DLLME in the Analysis of Metal Ions 266 Application of IL-DLLME in the Analysis of Organic Environmental Pollutants 266
- Published
- 2013
29. Detection of extraction artifacts in the analysis of honey volatiles using comprehensive two-dimensional gas chromatography
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Sanja Risticevic, Sandra Regina Rivellino, Eduardo Carasek, Janusz Pawliszyn, Leandro Wang Hantao, and Fabio Augusto
- Subjects
Quality Control ,Volatile Organic Compounds ,Chromatography, Gas ,Chromatography ,Extraction (chemistry) ,Analytical chemistry ,Sample preparation ,Food Contamination ,General Medicine ,Fractionation ,Honey ,Solid phase microextraction ,Mass spectrometry ,Solid-phase microextraction ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Kovats retention index ,Gas chromatography ,Extraction artifacts ,Brazil ,Hydroxymethylfurfural ,Comprehensive two-dimensional gas chromatography ,Food Science - Abstract
Extraction using headspace solid phase microextraction (HS-SPME) coupled to comprehensive two-dimensional gas chromatography with flame ionisation detection (GC×GC–FID) was employed to evaluate the effect of SPME fractionation conditions (heating time and temperature) on the generation of artifacts. The occurrence of artifacts was more pronounced at higher fractionation temperatures and times which caused significant changes in the chromatographic profiles. The identification of the volatile fraction of the honey blend was performed through a two-dimensional gas chromatograph coupled to a mass spectrometer with time of flight analyser (GC×GC–ToFMS) by comparing the first dimension linear temperature programmed retention index (1D-LTPRI) with the peak’s identities provided by the mass spectral similarity search. Several artifacts were found and identified – such as hydroxymethylfurfural, methyl–furone and furfural – and some of them were not previously detected as such in honey samples. These compounds were either the result of hydrolysis or thermal decomposition of components already present in the honey samples. This occurrence was attributed to the increased detectability provided by GC×GC compared to conventional GC. The possible emergence of previously unknown extraction artifacts as a general tendency related use of GC×GC instead of conventional GC is discussed as a result of these observations.
- Published
- 2013
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30. Comprehensive two-dimensional gas chromatography combined to multivariate data analysis for detection of disease-resistant clones of Eucalyptus
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Bruna R. Toledo, Edson Luiz Furtado, Leandro Wang Hantao, Marília Pizetta, Fabiana Alves de Lima Ribeiro, Caroline Geraldi Pierozzi, and Fabio Augusto
- Subjects
Analyte ,Multivariate analysis ,Chemistry(all) ,Analytical chemistry ,Metabolic profile ,Resistance biomarkers ,Mass spectrometry ,Solid-phase microextraction ,Rust ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,Plant Immunity ,Puccinia psidii ,Solid Phase Microextraction ,Plant Diseases ,Eucalyptus ,Volatile Organic Compounds ,Chromatography ,biology ,Chemistry ,Chimera ,food and beverages ,biology.organism_classification ,Plant Leaves ,Multivariate Analysis ,Parallel factor analysis ,Gas chromatography ,Biomarkers ,Comprehensive two-dimensional gas chromatography - Abstract
In this paper it is reported the use of the chromatographic profiles from volatile fractions of plant clones – in this case, hybrids of Eucalyptus grandis×Eucalyptus urophylla – to determine specimens susceptible to rust disease. The analytes were isolated by headspace solid phase microextraction (HS-SPME) and analyzed by comprehensive two-dimensional gas chromatography combined to fast quadrupole mass spectrometry (GC×GC-qMS). Parallel Factor Analysis (PARAFAC) was employed for estimate the correlation between the chromatographic profiles and resistance against Eucalyptus rust, after preliminary variable selection performed by Fisher ratio analysis. The proposed method allowed the differentiation between susceptible and non-susceptible clones and determination of three resistance biomarkers. This approach can be a valuable alternative for the otherwise time-consuming and labor-intensive methods commonly used.
- Published
- 2013
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31. Quantitative analysis of biodiesel in blends of biodiesel and conventional diesel by comprehensive two-dimensional gas chromatography and multivariate curve resolution
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Fabiana Alves de Lima Ribeiro, Monica Mamian Lopez, Fabio Augusto, Ronei J. Poppi, Noroska Gabriela Salazar Mogollón, and Leandro Wang Hantao
- Subjects
Flame Ionization ,Principal Component Analysis ,Multivariate curve resolution ,Biodiesel ,Chromatography, Gas ,Chromatography ,Chemistry ,Analytical chemistry ,Biochemistry ,Analytical Chemistry ,law.invention ,Diesel fuel ,law ,Biofuels ,Calibration ,Multivariate Analysis ,Principal component analysis ,Environmental Chemistry ,Two-dimensional gas ,Flame ionization detector ,Gas chromatography ,Quantitative analysis (chemistry) ,Gasoline ,Spectroscopy - Abstract
In this paper, a method to determine the composition of blends of biodiesel with mineral diesel (BXX) by multivariate curve resolution with Alternating Least Squares (MRC-ALS) combined to comprehensive two-dimensional gas chromatography with Flame Ionization Detection (GC×GC-FID) is presented. Chromatographic profiles of BXX blends produced with biodiesels from different sources were used as input data. An initial evaluation carried out after multiway principal component analysis (MPCA) was used to reveal regions of the chromatograms were the signal was likely to be dependent on the concentration of biodiesel, regardless its vegetable source. After this preliminary step MCR-ALS modeling was carried out only using relevant parts of the chromatograms. The resulting procedure was able to predict accurately the concentration of biodiesel in the BXX samples regardless of its origin.
- Published
- 2013
32. New materials and trends in sorbents for solid-phase extraction
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Leandro Wang Hantao, Soraia C.G.N. Braga, Fabio Augusto, and Noroska Gabriela Salazar Mogollón
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chemistry.chemical_classification ,Sorbent ,Materials science ,Biomolecule ,Extraction (chemistry) ,Ionic bonding ,Carbon nanotube ,Immunosorbents ,Analytical Chemistry ,law.invention ,Molecular recognition ,Chemical engineering ,chemistry ,law ,Organic chemistry ,Solid phase extraction ,Spectroscopy - Abstract
In this article, we outline and discuss some of the most recent tendencies on the research related to novel sorbent materials for solid-phase extraction (SPE). Hemimicelles and admicelles are structures formed from solutions of ionic surfactants, which can be sorbed on the surfaces of active solids, resulting in sorbents capable of simultaneously extracting a wide range of analytes with extremely varied polarity. The performance of another important class of new SPE materials is based on molecular recognition, which mimics the selective or specific affinity of several biomolecules towards their target compounds: these sorbents include molecularly-imprinted materials, immunosorbents and aptamer-modified surfaces. Finally, there is also a growing interest on sorbents based on nanostructured materials (e.g., electrospun nanofibers and carbon nanotubes).
- Published
- 2013
33. Solid-phase microextraction combined with comprehensive two-dimensional gas chromatography for fatty acid profiling of cell wall phospholipids
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Stanislau Bogusz, Dora Fix Ventura, Marcelo Fernandes da Costa, Valtenice de Cássia Rodrigues de Matos França, Russell D. Hamer, Leandro Wang Hantao, Fabio Augusto, and Soraia C.G.N. Braga
- Subjects
Detection limit ,Analyte ,Chromatography ,Chemistry ,Filtration and Separation ,Solid-phase microextraction ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,law ,Flame ionization detector ,Sample preparation ,Gas chromatography ,Derivatization ,Fatty acid methyl ester - Abstract
The combination of solid-phase microextraction (SPME) with comprehensive two-dimensional gas chromatography is evaluated here for fatty acid (FA) profiling of the glycerophospholipid fraction from human buccal mucosal cells. A base-catalyzed derivatization reaction selective for polar lipids such as glycerophospholipid was adopted. SPME is compared to a miniaturized liquid-liquid extraction procedure for the isolation of FA methyl esters produced in the derivatization step. The limits of detection and limits of quantitation were calculated for each sample preparation method. Because of its lower values of limits of detection and quantitation, SPME was adopted. The extracted analytes were separated, detected, and quantified by comprehensive two-dimensional gas chromatography with flame ionization detection (FID). The combination of SPME and comprehensive two-dimensional gas chromatography with FID, using a selective derivatization reaction in the preliminary steps, proved to be a simple and fast procedure for FA profiling, and was successfully applied to the analysis of adult human buccal mucosal cells.
- Published
- 2012
34. Multivariate curve resolution combined with gas chromatography to enhance analytical separation in complex samples: A review
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Guilherme P. Sabin, Helga Gabriela Aleme, Marcio Pozzobon Pedroso, Leandro Wang Hantao, Fabio Augusto, and Ronei J. Poppi
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Multivariate statistics ,Chromatography ,Resolution (mass spectrometry) ,business.industry ,Chemistry ,Orthographic projection ,Pattern recognition ,Chemical Fractionation ,Mass spectrometry ,Biochemistry ,Least squares ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,law.invention ,Chemometrics ,law ,Multivariate Analysis ,Environmental Chemistry ,Flame ionization detector ,Gas chromatography ,Artificial intelligence ,Least-Squares Analysis ,business ,Spectroscopy - Abstract
This review describes the major advantages and pitfalls of iterative and non-iterative multivariate curve resolution (MCR) methods combined with gas chromatography (GC) data using literature published since 2000 and highlighting the most important combinations of GC coupled to mass spectrometry (GC–MS) and comprehensive two-dimensional gas chromatography with flame ionization detection (GC × GC-FID) and coupled to mass spectrometry (GC × GC–MS). In addition, a brief summary of some pre-processing strategies will be discussed to correct common issues in GC, such as retention time shifts and baseline/background contributions. Additionally, algorithms such as evolving factor analysis (EFA), heuristic evolving latent projection (HELP), subwindow factor analysis (SFA), multivariate curve resolution-alternating least squares (MCR-ALS), positive matrix factorization (PMF), iterative target transformation factor analysis (ITTFA) and orthogonal projection resolution (OPR) will be described in this paper. Even more, examples of applications to food chemistry, lipidomics and medicinal chemistry, as well as in essential oil research, will be shown. Lastly, a brief illustration of the MCR method hierarchy will also be presented.
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- 2012
35. Quantitative analysis of essential oils in perfume using multivariate curve resolution combined with comprehensive two-dimensional gas chromatography
- Author
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Ronei J. Poppi, Fabio Augusto, Luiz Antonio Fonseca de Godoy, Marcio Pozzobon Pedroso, and Leandro Wang Hantao
- Subjects
Flame Ionization ,Multivariate statistics ,Chromatography, Gas ,Chromatography ,Calibration curve ,Chemistry ,Biochemistry ,Rosmarinus ,Perfume ,Analytical Chemistry ,law.invention ,Standard curve ,Two-dimensional chromatography ,law ,Oils, Volatile ,Calibration ,Environmental Chemistry ,Flame ionization detector ,Gas chromatography ,Cymbopogon ,Least-Squares Analysis ,Algorithms ,Spectroscopy ,Essential oil - Abstract
The use of multivariate curve resolution (MCR) to build multivariate quantitative models using data obtained from comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC-FID) is presented and evaluated. The MCR algorithm presents some important features, such as second order advantage and the recovery of the instrumental response for each pure component after optimization by an alternating least squares (ALS) procedure. A model to quantify the essential oil of rosemary was built using a calibration set containing only known concentrations of the essential oil and cereal alcohol as solvent. A calibration curve correlating the concentration of the essential oil of rosemary and the instrumental response obtained from the MCR-ALS algorithm was obtained, and this calibration model was applied to predict the concentration of the oil in complex samples (mixtures of the essential oil, pineapple essence and commercial perfume). The values of the root mean square error of prediction (RMSEP) and of the root mean square error of the percentage deviation (RMSPD) obtained were 0.4% (v/v) and 7.2%, respectively. Additionally, a second model was built and used to evaluate the accuracy of the method. A model to quantify the essential oil of lemon grass was built and its concentration was predicted in the validation set and real perfume samples. The RMSEP and RMSPD obtained were 0.5% (v/v) and 6.9%, respectively, and the concentration of the essential oil of lemon grass in perfume agreed to the value informed by the manufacturer. The result indicates that the MCR algorithm is adequate to resolve the target chromatogram from the complex sample and to build multivariate models of GC×GC-FID data.
- Published
- 2011
36. Identification of volatiles from pineapple (Ananas comosus L.) pulp by comprehensive two-dimensional gas chromatography and gas chromatography/mass spectrometry
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Fabio Augusto, Ernesto Correa Ferreira, Marcio Pozzobon Pedroso, Stanislau Bogusz, and Leandro Wang Hantao
- Subjects
Chromatography ,Chemistry ,Extraction (chemistry) ,Analytical chemistry ,Filtration and Separation ,Solid-phase microextraction ,Mass spectrometry ,Analytical Chemistry ,law.invention ,Two-dimensional chromatography ,law ,Flame ionization detector ,Sample preparation ,Gas chromatography ,Gas chromatography–mass spectrometry - Abstract
Combining qualitative data from the chromatographic structure of 2-D gas chromatography with flame ionization detection (GC×GC-FID) and that from gas chromatography-mass spectrometry (GC/MS) should result in a more accurate assignment of the peak identities than the simple analysis by GC/MS, where coelution of analytes is unavoidable in highly complex samples (rendering spectra unsuitable for qualitative purposes) or for compounds in very low concentrations. Using data from GC×GC-FID combined with GC/MS can reveal coelutions that were not detected by mass spectra deconvolution software. In addition, some compounds can be identified according to the structure of the GC×GC-FID chromatogram. In this article, the volatile fractions of fresh and dehydrated pineapple pulp were evaluated. The extraction of the volatiles was performed by dynamic headspace extraction coupled to solid-phase microextraction (DHS-SPME), a technique appropriate for slurries or solid matrices. Extracted analytes were then analyzed by GC×GC-FID and GC/MS. The results obtained using both techniques were combined to improve compound identifications.
- Published
- 2011
37. IONIC LIQUID STATIONARY PHASES IN GAS CHROMATOGRAPHY: FUNDAMENTALS, RECENT ADVANCES, AND PERSPECTIVES
- Author
-
Leandro Wang Hantao, Bruna R. Toledo, and Fabio Augusto
- Subjects
chemistry.chemical_compound ,chemistry ,Vapor pressure ,Ionic liquid ,Solvation ,Analytical chemistry ,Melting point ,Context (language use) ,General Chemistry ,Gas chromatography ,Selectivity ,Ion - Abstract
Since their original discovery in 1914, ionic liquids (IL) have been widely examined and explored in chemistry due to their unique physical and chemical properties. Ionic liquids are collectively known as organic salts and have melting points of 100 °C or under. The molten salts most employed in analytical chemistry, including gas chromatography (GC), consist of an organic cation paired with an organic or inorganic anion. This class of materials exhibits negligible vapor pressure and may have their properties (e.g.thermal stability and selectivity) structurally tuned by imparting different moieties to the cation/anion. Currently, there are an estimated 1018possible combinations of IL. In this context, the prospection of highly selective IL-based stationary phases for gas-liquid chromatography has enabled high peak capacity and efficient separations of many critical pairs in complex samples. In this review, we present and discuss fundamental characteristics of ionic liquids and introduce important solvation models for gas-liquid systems. In addition, recent advances and applications of IL in conventional and multidimensional gas chromatography are outlined.
- Published
- 2015
38. Identifying important structural features of ionic liquid stationary phases for the selective separation of nonpolar analytes by comprehensive two-dimensional gas chromatography
- Author
-
Isaiah C. Ingram, Jared L. Anderson, Leandro Wang Hantao, and Cheng Zhang
- Subjects
Ions ,Chromatography ,Chromatography, Gas ,Resolution (mass spectrometry) ,Component (thermodynamics) ,Organic Chemistry ,Solvation ,Temperature ,Ionic Liquids ,General Medicine ,Models, Theoretical ,Biochemistry ,Analytical Chemistry ,Ion ,Kerosene ,chemistry.chemical_compound ,chemistry ,Ionic liquid ,Two-dimensional gas ,Gas chromatography ,Selectivity - Abstract
A series of dicationic ionic liquid (IL)-based stationary phases were evaluated as secondary columns in comprehensive two-dimensional gas chromatography (GC×GC) for the separation of aliphatic hydrocarbons from kerosene. In order to understand the role that structural features of ILs play on the selectivity of nonpolar analytes, the solvation parameter model was used to probe the solvation properties of the IL-based stationary phases. It was observed that room temperature ILs containing long free alkyl side chain substituents and long linker chains between the two cations possess less cohesive forces and exhibited the highest resolution of aliphatic hydrocarbons. The anion component of the IL did not contribute significantly to the overall separation, as similar selectivities toward aliphatic hydrocarbons were observed when examining ILs with identical cations and different anions. In an attempt to further examine the separation capabilities of the IL-based GC stationary phases, columns of the best performing stationary phases were prepared with higher film thickness and resulted in enhanced selectivity of aliphatic hydrocarbons.
- Published
- 2014
39. Chemical immobilization of crosslinked polymeric ionic liquids on nitinol wires produces highly robust sorbent coatings for solid-phase microextraction
- Author
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Leandro Wang Hantao, Tien D. Ho, Bruna R. Toledo, and Jared L. Anderson
- Subjects
Sorbent ,Analytical chemistry ,engineering.material ,Solid-phase microextraction ,Biochemistry ,Analytical Chemistry ,chemistry.chemical_compound ,Monomer ,chemistry ,Chemical engineering ,Coating ,Nickel titanium ,Ionic liquid ,Copolymer ,engineering ,Environmental Chemistry ,Derivatization ,Spectroscopy - Abstract
Super elastic nitinol (NiTi) wires were exploited as highly robust supports for three distinct crosslinked polymeric ionic liquid (PIL)-based coatings in solid-phase microextraction (SPME). The oxidation of NiTi wires in a boiling (30% w/w) H2O2 solution and subsequent derivatization in vinyltrimethoxysilane (VTMS) allowed for vinyl moieties to be appended to the surface of the support. UV-initiated on-fiber copolymerization of the vinyl-substituted NiTi support with monocationic ionic liquid (IL) monomers and dicationic IL crosslinkers produced a crosslinked PIL-based network that was covalently attached to the NiTi wire. This alteration alleviated receding of the coating from the support, which was observed for an analogous crosslinked PIL applied on unmodified NiTi wires. A series of demanding extraction conditions, including extreme pH, pre-exposure to pure organic solvents, and high temperatures, were applied to investigate the versatility and robustness of the fibers. Acceptable precision of the model analytes was obtained for all fibers under these conditions. Method validation by examining the relative recovery of a homologous group of phthalate esters (PAEs) was performed in drip-brewed coffee (maintained at 60 °C) by direct immersion SPME. Acceptable recoveries were obtained for most PAEs in the part-per-billion level, even in this exceedingly harsh and complex matrix.
- Published
- 2014
40. Tuning the selectivity of ionic liquid stationary phases for enhanced separation of nonpolar analytes in kerosene using multidimensional gas chromatography
- Author
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Ali Najafi, Fabio Augusto, Cheng Zhang, Leandro Wang Hantao, and Jared L. Anderson
- Subjects
Analyte ,chemistry.chemical_compound ,Kerosene ,Chromatography ,Resolution (mass spectrometry) ,Chemistry ,Ionic liquid ,Analytical chemistry ,Solvation ,Phosphonium ,Gas chromatography ,Selectivity ,Analytical Chemistry - Abstract
In this study, a series of ionic liquids (ILs) are evaluated as stationary phases in comprehensive two-dimensional gas chromatography (GC × GC) for the separation of aliphatic hydrocarbons from kerosene. IL-based stationary phases were carefully designed to evaluate the role of cavity formation/dispersive interaction on the chromatographic retention of nonpolar analytes by GC × GC. The maximum allowable operating temperature (MAOT) of the IL-based columns was compared to that of commercial IL-based columns. Evaluation of the solvation characteristics of GC columns guided the selection of the best performing IL-based stationary phases for the resolution of aliphatic hydrocarbons, namely, trihexyl(tetradecyl)phosphonium tetrachloroferrate ([P66614][FeCl4]) and trihexyl(tetradecyl)phosphonium tris(pentafluoroethyl)trifluorophosphate ([P66614][FAP]) ILs. The best performing [P66614][FeCl4] IL-based column exhibited a MAOT of 320 °C, higher than the commercial SUPELCOWAX 10 (MAOT of 280 °C) and commercial IL-based columns (MAOT up to 300 °C). The structurally tuned [P66614][FeCl4] IL stationary phase exhibited improved separation of aliphatic hydrocarbons by GC × GC compared to the commercial columns examined (e.g., OV-1701, SUPELCOWAX 10, SLB-IL60, SLB-IL100, and SLB-IL111).
- Published
- 2014
41. A chemometric approach toward the detection and quantification of coffee adulteration by solid-phase microextraction using polymeric ionic liquid sorbent coatings
- Author
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Fabio Augusto, Tien D. Ho, Leandro Wang Hantao, Bruna R. Toledo, and Jared L. Anderson
- Subjects
Adulterant ,Analyte ,Sorbent ,Chromatography ,Chemistry ,Dodecane ,Polymers ,Organic Chemistry ,Ionic Liquids ,Coffea ,General Medicine ,Mass spectrometry ,Solid-phase microextraction ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,Analytical Chemistry ,chemistry.chemical_compound ,Food Quality ,Food Technology ,Regression Analysis ,Gas chromatography ,Gas chromatography–mass spectrometry ,Solid Phase Microextraction - Abstract
Solid-phase microextraction (SPME) using cross-linked polymeric ionic liquid (PIL)-based sorbent coatings was used to extract volatile aroma-related compounds from coffee samples. Several PIL-based coatings were screened alongside a commercial poly(acrylate) (PA) SPME coating. The best performing PIL-based SPME fiber, poly(1-vinyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonylimide]) with 50% (w/w) 1,12-di(3-vinylbenzylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide incorporated cross-linker, was used to isolate the volatile fraction of Arabica coffee. To illustrate the importance of trace analyte isolation, a method for the detection and quantification of coffee adulteration is described. Chromatographic profiles obtained by gas chromatography/mass spectrometry (GC/MS) were used to create the chemometric model. Partial least squares (PLS) regression was employed to correlate the aroma-related chemical fingerprint to the degree of adulteration. The proposed method successfully detected fraud down to 1% (w/w) of adulterant and accurately determined the degree of coffee adulteration (i.e, root mean square error of calibration and prediction of 0.54% and 0.83% (w/w), respectively). Finally, important aroma-related compounds including furans, methoxyphenols, pyrazines, and ketones were identified.
- Published
- 2014
42. Determination of fuel origin by comprehensive 2D GC-FID and parallel factor analysis
- Author
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Fabio Augusto, Marcio Pozzobon Pedroso, Ronei J. Poppi, Leandro Wang Hantao, and Luiz Antonio Fonseca de Godoy
- Subjects
gasoline ,Chromatography ,comprehensive two-dimensional gas chromatography ,multivariate analysis ,Chemistry ,pattern recognition ,General Chemistry ,parallel factor analysis ,Gasoline - Abstract
In this work, a method for differentiation of gasoline according to its geographical origin is presented. Comprehensive two-dimensional gas chromatography-flame ionization detection (GC×GC-FID) combined with multivariate analysis was used to differentiate Brazilian and Venezuelan gasoline samples. Pattern recognition of the GC×GC-FID chromatograms was performed by parallel factor analysis (PARAFAC) and it was successfully applied for the differentiation of these gasoline samples. Eluates with medium to high volatility, both aliphatic and aromatic, were responsible for this differentiation, based on the inspection of the score and loading graphs generated by PARAFAC. Neste trabalho, um método para a diferenciação de gasolinas de acordo com a sua origem geográfica é proposto. Cromatografia gasosa bidimensional abrangente com detecção por ionização em chama (GC×GC-FID) em conjunto com a análise multivariada foi utilizada para diferenciar amostras de gasolina brasileira de amostras oriundas da Venezuela. A análise de fatores paralelos (PARAFAC) foi utilizada no reconhecimento de padrões dos cromatogramas GC×GC-FID e foi aplicada com êxito na diferenciação das amostras de gasolina. Através da análise dos gráficos de escores e pesos gerados pela análise PARAFAC, foi possível determinar que eluatos de média a alta volatilidade, tanto alifáticos quanto aromáticos, foram responsáveis por essa diferenciação.
- Published
- 2013
43. Determination of disease biomarkers in Eucalyptus by comprehensive two-dimensional gas chromatography and multivariate data analysis
- Author
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Fabiana Alves de Lima Ribeiro, Martha Maria Passador, Helga Gabriela Aleme, Fabio Augusto, Ronei J. Poppi, Edson Luiz Furtado, and Leandro Wang Hantao
- Subjects
Analyte ,Eucalyptus ,Volatile Organic Compounds ,Chromatography ,Chromatography, Gas ,biology ,Chemistry ,Organic Chemistry ,General Medicine ,Mass spectrometry ,Solid-phase microextraction ,Linear discriminant analysis ,biology.organism_classification ,Biochemistry ,Least squares ,Analytical Chemistry ,Plant Leaves ,Ascomycota ,Eucalyptus globulus ,Partial least squares regression ,Multivariate Analysis ,Gas chromatography ,Biomarkers ,Plant Diseases - Abstract
In this paper is reported the use of the chromatographic profiles of volatiles to determine disease markers in plants – in this case, leaves of Eucalyptus globulus contaminated by the necrotroph fungus Teratosphaeria nubilosa . The volatile fraction was isolated by headspace solid phase microextraction (HS-SPME) and analyzed by comprehensive two-dimensional gas chromatography–fast quadrupole mass spectrometry (GC × GC–qMS). For the correlation between the metabolic profile described by the chromatograms and the presence of the infection, unfolded-partial least squares discriminant analysis (U-PLS-DA) with orthogonal signal correction (OSC) were employed. The proposed method was checked to be independent of factors such as the age of the harvested plants. The manipulation of the mathematical model obtained also resulted in graphic representations similar to real chromatograms, which allowed the tentative identification of more than 40 compounds potentially useful as disease biomarkers for this plant/pathogen pair. The proposed methodology can be considered as highly reliable, since the diagnosis is based on the whole chromatographic profile rather than in the detection of a single analyte.
- Published
- 2012
44. Quantitative analysis by comprehensive two-dimensional gas chromatography using interval Multi-way Partial Least Squares calibration
- Author
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Fabio Augusto, Luiz Antonio Fonseca de Godoy, Marcio Pozzobon Pedroso, Ronei J. Poppi, and Leandro Wang Hantao
- Subjects
Analyte ,Accuracy and precision ,Chromatography ,Chromatography, Gas ,Chemistry ,Statistics as Topic ,Allergens ,Analytical Chemistry ,Perfume ,Two-dimensional chromatography ,Partial least squares regression ,Calibration ,Feasibility Studies ,Gas chromatography ,Least-Squares Analysis ,MATLAB ,computer ,Quantitative analysis (chemistry) ,Algorithms ,computer.programming_language - Abstract
A new approach for target quantitative analysis for comprehensive two-dimensional gas chromatography (GC × GC), interval Multi-way Partial Least Square (iNPLS) is presented and evaluated in this paper. In iNPLS, the two-dimensional chromatogram is split in small sections; each of these pieces is treated as an independent new chromatogram. Separated conventional NPLS calibration models for the concentration of the target analyte are built for each of the pieces of the whole chromatogram, and the best model is selected for quantitative analysis. An algorithm for iNPLS running on MatLab platform was written, preliminarily evaluated with using solutions of model compounds with different chemical properties and subsequently applied to quantify some allergens in perfume samples. The results were found to be adequate, and good precision and accuracy was obtained even for poorly resolved peaks.
- Published
- 2010
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