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1.
Anal Bioanal Chem ; 416(2): 449-459, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37987769

RESUMO

In this work, a complete study of the distribution of emerging mycotoxins in the human body has been carried out. Specifically, the presence of enniatins (A, A1, B, B1) and beauvericin has been monitored in brain, lung, kidney, fat, liver, and heart samples. A unique methodology based on solid-liquid extraction (SLE) followed by dispersive liquid-liquid microextraction (DLLME) was proposed for the six different matrices. Mycotoxin isolation was performed by adding ultrapure water, acetonitrile, and sodium chloride to the tissue sample for SLE, while the DLLME step was performed using chloroform as extraction solvent. Subsequently, the analysis was carried out by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). The proposed method allowed limits of quantification (LOQs) to be obtained in a range of 0.001-0.150 ng g-1, depending on the tissue and mycotoxin. The precision was investigated intraday and interday, not exceeding of 9.8% of relative standard deviation. In addition, trueness studies achieved 75 to 115% at a mycotoxin concentration of 25 ng g-1 and from 82 to 118% at 5 ng g-1. The application of this methodology to 26 forensic autopsies demonstrated the bioaccumulation of emerging mycotoxins in the human body since all mycotoxins were detected in tissues. Enniatin B (ENNB) showed a high occurrence, being detected in 100% of liver (7 ± 13 ng g-1) and fat samples (0.2 ± 0.8 ng g-1). The lung had a high incidence of all emerging mycotoxins at low concentrations, while ENNB, ENNB1, and ENNA1 were not quantifiable in heart samples. Co-occurrence of mycotoxins was also investigated, and statistical tests were applied to evaluate the distribution of these mycotoxins in the human body.


Assuntos
Microextração em Fase Líquida , Micotoxinas , Humanos , Espectrometria de Massa com Cromatografia Líquida , Espectrometria de Massas em Tandem/métodos , Micotoxinas/análise , Cromatografia Líquida de Alta Pressão
2.
Anal Bioanal Chem ; 415(11): 2133-2145, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36695870

RESUMO

A new analytical method based on the use of dispersive magnetic solid-phase extraction (DMSPE) is described for the preconcentration of capsaicin (CAP), dihydrocapsaicin (DCAP), and N-vanillylnonanamide (PCAP) from human serum samples. The influence of several experimental factors affecting the adsorption (nature and amount of magnetic material, adsorption time, and pH) and desorption (nature of solvent, its volume and desorption time) steps was studied. Among seven different nanomaterials studied, the best results were obtained using magnetic multiwalled carbon nanotubes, which were characterized by means of spectrometry- and microscopy-based techniques. Analyses were performed by ultra-high-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry using electrospray ionization in positive mode (UHPLC-ESI-Q-TOF-MS). The developed method was validated by obtaining several parameters, including linearity (0.3-300 µg L-1 range), and limits of detection which were 0.1, 0.15, and 0.17 µg L-1 for CAP, DCAP, and PCAP, respectively. The repeatability of the method, expressed as relative standard deviation (RSD, n = 7), varied from 3.4 to 11%. The serum samples were also studied through a non-targeted approach in a search for capsaicinoid metabolites and related compounds. With this objective, the fragmentation pathway of this family of compounds was initially studied and a strategy was established for the identification of novel or less studied capsaicinoid-derived compounds.


Assuntos
Nanotubos de Carbono , Humanos , Capsaicina/química , Capsaicina/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Fenômenos Magnéticos , Espectrometria de Massas , Nanotubos de Carbono/química , Extração em Fase Sólida/métodos
3.
Anal Bioanal Chem ; 415(17): 3571-3579, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37233766

RESUMO

Inflammatory bowel disease (IBD) diagnosis depends on criteria based on histological, endoscopic, radiological, and clinical results. These studies show drawbacks as being expensive, invasive, and time-consuming. In this work, an untargeted metabolomic strategy based on the monitoring of volatile compounds in serum by headspace gas chromatography-mass spectrometry is proposed as a complementary, fast, and efficient test for IBD patient diagnosis. To develop the method and build a chemometric model that allows the IBD diagnosis, serum samples including IBD patients and healthy volunteers were collected. Analyses were performed by incubating 400 µL of serum for 10 min at 90 °C. For data processing, an untargeted metabolomic strategy was used. A total of 96 features were detected, of which a total of 10 volatile compounds could be identified and confirmed by means of the analysis of real standards. The chemometric treatment consisted of a discriminant analysis of orthogonal partial least squares (OPLS-DA) obtaining a 100% of classification rate, since all the analyzed samples were correctly classified.


Assuntos
Doenças Inflamatórias Intestinais , Compostos Orgânicos Voláteis , Humanos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Doenças Inflamatórias Intestinais/diagnóstico , Análise Discriminante , Metabolômica/métodos , Análise dos Mínimos Quadrados , Compostos Orgânicos Voláteis/análise
4.
J Sep Sci ; 46(17): e2300207, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37403284

RESUMO

Hydroxylated polycyclic aromatic hydrocarbons are metabolites of persistent organic pollutants which are formed during the bioactivation process of biological matrices and whose toxicity is being studied. The aim of this work was the development of a novel analytical method for the determination of these metabolites in human tissues, known to have bioaccumulated their parent compounds. Samples were treated by salting-out assisted liquid-liquid extraction and the extracts were analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry with a hybrid quadrupole-time-of-flight analyzer. The proposed method achieved limits of detection in the 0.15-9.0 ng/g range for the five target analytes (1-hydroxynaphthalene, 1-hydroxypyrene, 2-hydroxynaphthalene, 7-hydroxybenzo[a]pyrene, and 9-hydroxyphenanthrene). The quantification was achieved by matrix-matched calibration using 2,2´-biphenol as internal standard. For all compounds, relative standard deviation, calculated for six successive analyses, was below 12.1%, demonstrating good precision for the developed method. None of the target compounds was detected in the 34 studied samples. Moreover, an untargeted approach was applied to study the presence of other metabolites in the samples, as well as their conjugated forms and related compounds. For this objective, a homemade mass spectrometry database covering 81 compounds was created and none of them was detected in the samples.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Humanos , Hidrocarbonetos Policíclicos Aromáticos/análise , Espectrometria de Massas , Cromatografia Líquida , Cromatografia Líquida de Alta Pressão/métodos , Calibragem
5.
Mikrochim Acta ; 190(5): 178, 2023 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-37022520

RESUMO

An analytical methodology based on the combination of dispersive magnetic solid-phase extraction (DMSPE) and liquid chromatography-mass spectrometry (LC-MS) is proposed to explore the occurrence of 13 mycotoxins (aflatoxins B1, G1, B2, and G2; deoxynivalenol; T-2 toxin; ochratoxin A; HT-2 toxin; enniatins A, A1, B, and B2; and beauvericin) and their derivatives in natural grass samples. Magnetic microparticles (Fe3O4) coated with polypyrrole (PPy) polymer were used in DMSPE sample treatment as adsorbent phase, and Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy have been used for its characterization. The experimental parameters influencing the adsorption and desorption steps of DMSPE have been optimized. Method validation has been carried out obtaining limits of quantification between 0.07 and 92 µg kg-1 corresponding to enniatin B or A1 and DON, respectively. A total of 83 natural grass samples from 8 dehesa farms were analysed. Enniatin B was found in all the samples (0.29 to 488 µg kg-1 concentration range) followed by enniatin B1 (92.8% of the samples) with a 0.12-137 µg kg-1 concentration range. Moreover, co-occurrence of mycotoxins was studied and between 2 and 5 mycotoxins appeared simultaneously in 97.6% of the samples. Distribution of the contamination according to natural grass location was also investigated.


Assuntos
Micotoxinas , Micotoxinas/análise , Polímeros , Pirróis , Poaceae , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida
6.
Molecules ; 28(11)2023 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-37298771

RESUMO

The botanical origin of honey determines its composition and hence properties and product quality. As a highly valued food product worldwide, assurance of the authenticity of honey is required to prevent potential fraud. In this work, the characterisation of Spanish honeys from 11 different botanical origins was carried out by headspace gas chromatography coupled with mass spectrometry (HS-GC-MS). A total of 27 volatile compounds were monitored, including aldehydes, alcohols, ketones, carboxylic acids, esters and monoterpenes. Samples were grouped into five categories of botanical origins: rosemary, orange blossom, albaida, thousand flower and "others" (the remaining origins studied, due to the limitation of samples available). Method validation was performed based on linearity and limits of detection and quantification, allowing the quantification of 21 compounds in the different honeys studied. Furthermore, an orthogonal partial least squares-discriminant analysis (OPLS-DA) chemometric model allowed the classification of honey into the five established categories, achieving a 100% and 91.67% classification and validation success rate, respectively. The application of the proposed methodology was tested by analysing 16 honey samples of unknown floral origin, classifying 4 as orange blossom, 4 as thousand flower and 8 as belonging to other botanical origins.


Assuntos
Mel , Compostos Orgânicos Voláteis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Mel/análise , Compostos Orgânicos Voláteis/análise , Análise Discriminante , Flores/química
7.
J Sep Sci ; 45(15): 2996-3004, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35713621

RESUMO

Fifteen aroma compounds have been determined in their free and glycosylated forms in grapes using dispersive liquid-liquid microextraction with gas chromatography-mass spectrometry. The sample treatment includes a previous solid-liquid extraction stage and subsequent parallel microextraction approaches to preconcentrate total aroma content and the free fraction. Thus, the extraction of the total content of analytes requires previous enzymatic hydrolysis of the bound forms. For preconcentration, chloroform (250 µl) and acetonitrile (1.5 ml) were added to 10 ml of the sample extract in the presence of 0.5 g sodium chloride. The absence of matrix effect in the samples allowed quantification against aqueous external standards. Limits of detection ranged between 5 and 30 ng/g, depending on the compound. Method accuracy was studied through recovery assays, with recoveries in the 82-115% range being obtained. Relative standard deviations for repeatability studies were lower than 12%. Four different samples of grapes were analyzed, being quantified linalool in its free form at concentrations in the 359-470 ng/g range, and benzyl alcohol, 2-phenylethanol, and linalool oxide I and II in their bound forms between 52 and 464 ng/g.


Assuntos
Microextração em Fase Líquida , Vitis , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Líquida/métodos , Odorantes , Água
8.
Chem Res Toxicol ; 32(8): 1680-1688, 2019 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-31304742

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are considered xenobiotics of a potentially carcinogenic nature, being accumulated in the fatty tissue of the body. The objective of this work was the development and validation of a new analytical method to check the bioaccumulation of these toxic compounds in human organs obtained from autopsies. The contaminants were first isolated from the tissues by salt-assisted liquid-liquid extraction in acetonitrile. Because of the low concentrations of these compounds in the human body, a dispersive liquid-liquid microextraction procedure was included. The preconcentrated samples were analyzed by gas chromatography-mass spectrometry to identify the compounds. Principal component analysis was applied to show the natural clustering of forensic samples and orthogonal partial least-squares discriminant analysis to develop a multivariate regression method, which permitted the classification of samples. The quantification limits for the 13 PAHs (acenaphthylene, fluorene, phenanthrene, anthracene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, and indeno(1,2,3-cd)pyrene) analyzed were in the 0.06-0.44 ng g-1 range, depending on the compound, while the mean intraday relative standard deviation of about 7% demonstrated the high precision of the method. Linearity was verified in the 0.5-200 ng g-1 range, and the enrichment factors were between 55 and 122. The results provided by the analysis of seven different human organs (brain, liver, kidney, lung, heart, spleen, and abdominal fat) from eight autopsies confirmed the PAH-bioaccumulation capacity of human body, fat showing the highest degree of bioaccumulation. The present work is the first study on PAH contamination in different organs obtained from autopsies, being PAH detected in most human samples at values ranged from 0 to 19 ng g-1.


Assuntos
Bioacumulação , Medicina Legal , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/farmacocinética , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Distribuição Tecidual
9.
J Sep Sci ; 41(12): 2565-2575, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29603660

RESUMO

The determination of 15 pyrethroids in soil and water samples was carried out by gas chromatography with mass spectrometry. Compounds were extracted from the soil samples (4 g) using solid-liquid extraction and then salting-out assisted liquid-liquid extraction. The acetonitrile phase obtained (0.8 mL) was used as a dispersant solvent, to which 75 µL of chloroform was added as an extractant solvent, submitting the mixture to dispersive liquid-liquid microextraction. For the analysis of water samples (40 mL), magnetic solid-phase extraction was performed using nanocomposites of magnetic nanoparticles and multiwalled carbon nanotubes as sorbent material (10 mg). The mixture was shaken for 45 min at room temperature before separation with a magnet and desorption with 3 mL of acetone using ultrasounds for 5 min. The solvent was evaporated and reconstituted with 100 µL acetonitrile before injection. Matrix-matched calibration is recommended for quantification of soil samples, while water samples can be quantified by standards calibration. The limits of detection were in the range of 0.03-0.5 ng/g (soil) and 0.09-0.24 ng/mL (water), depending on the analyte. The analyzed environmental samples did not contain the studied pyrethroids, at least above the corresponding limits of detection.

10.
J Sep Sci ; 40(6): 1310-1317, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28106340

RESUMO

A new procedure is proposed for the analysis of migration test solutions obtained from plastic bottles used in the packaging of edible oils. Ultrasound-assisted emulsification microextraction with ionic liquids was applied for the preconcentration of six phthalate esters: dimethylphthalate, diethylphthalate, di-n-butylphthalate, n-butylbenzylphthalate, di-2-ethylhexylphthalate, and di-n-octylphthalate. The enriched ionic liquid was directly analyzed by gas chromatography and mass spectrometry using direct insert microvial thermal desorption. The different factors affecting the microextraction efficiency, such as volume of the extracting phase (30 µL of the ionic liquid) and ultrasound application time (25 s), and the thermal desorption step, such as desorption temperature and time, and gas flow rate, were studied. Under the selected conditions, detection limits for the analytes were in the 0.012-0.18 µg/L range, while recovery assays provided values ranging from 80 to 112%. The use of butyl benzoate as internal standard increased the reproducibility of the analytical procedure. When the release of the six phthalate esters from the tested plastic bottles to liquid simulants was monitored using the optimized procedure, analyte concentrations of between 1.0 and 273 µg/L were detected.

11.
Anal Bioanal Chem ; 408(1): 243-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26476920

RESUMO

A new procedure based on direct insert microvial thermal desorption injection allows the direct analysis of ionic liquid extracts by gas chromatography and mass spectrometry (GC-MS). For this purpose, an in situ ionic liquid dispersive liquid-liquid microextraction (in situ IL DLLME) has been developed for the quantification of bisphenol A (BPA), bisphenol Z (BPZ) and bisphenol F (BPF). Different parameters affecting the extraction efficiency of the microextraction technique and the thermal desorption step were studied. The optimized procedure, determining the analytes as acetyl derivatives, provided detection limits of 26, 18 and 19 ng L(-1) for BPA, BPZ and BPF, respectively. The release of the three analytes from plastic containers was monitored using this newly developed analytical method. Analysis of the migration test solutions for 15 different plastic containers in daily use identified the presence of the analytes at concentrations ranging between 0.07 and 37 µg L(-1) in six of the samples studied, BPA being the most commonly found and at higher concentrations than the other analytes.

12.
J Sep Sci ; 39(12): 2292-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27130271

RESUMO

A rapid and simple procedure is reported for the determination of six ethylene glycol ethers in cleaning products and detergents using gas chromatography with mass spectrometry. The analytes were extracted from 2.0 g samples in acetonitrile (3 mL) and the extract was submitted to a clean-up step by QuEChERS method, using a mixture containing 0.3 g magnesium sulfate, 0.15 g primary/secondary amine, and 0.05 g C18 . The clean acetonitrile extract (1 µL) was injected into the chromatographic system. No matrix effect was observed, so the quantification of the samples was carried out against external standards. Detection limits were in the range 3.0-27 ng/g for the six ethylene glycol ethers. The recoveries obtained, using the optimized procedure, were in the 89.4-118% range, with relative standard deviations lower than 14%. Twenty-three different household cleaning products, including glass cleaner, degreaser, floor, softeners, and clothes and dishwashing detergents, were analyzed. Large interindividual variations were observed between samples and compounds.

13.
Anal Bioanal Chem ; 406(8): 2067-99, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24071895

RESUMO

An extensive critical evaluation of the application of dispersive liquid-liquid microextraction (DLLME) combined with chromatographic and atomic-spectroscopic methods for the determination of organic and inorganic compounds is presented. The review emphasizes the procedures used for the prior treatment of food samples, which are very different from the DLLME procedures generally proposed for water samples. The main contribution of this work in the field of DLLME reviews is its critical review of the abundant literature showing the increasing interest and practical advantages of using DLLME and closely related microextraction techniques for food analysis.


Assuntos
Análise de Alimentos/métodos , Microextração em Fase Líquida/métodos , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Microextração em Fase Líquida/instrumentação
14.
Toxins (Basel) ; 16(3)2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38535785

RESUMO

Magnetic molecularly imprinted polymers (MMIPs) have fused molecular imprinting technology with magnetic separation technology, emerging as an innovative material capable of recognizing specific molecules and efficiently separating target substances. Their application to the extraction and purification of mycotoxins has great potential, due to the toxicity and economic impact of these contaminants. In this work, MMIP has been proposed as a sample treatment for the determination of main four aflatoxins (B1, B2, G1 and G2) in pig feed. The MMIP was formed through the integration of magnetic material (Fe3O4) with commercial molecularly imprinted polymers, avoiding the synthesis step and, therefore, simplifying the process. The analyses were carried out by high-performance liquid chromatography with fluorescence detection and the method was validated and limits of quantification (LOQs) between 0.09 and 0.47 ng/g were obtained, below the allowed or recommended levels by the European Union. Repeatability and intermediate precision showed relative standard deviations lower than 10% in all cases and trueness ranged from 92 to 111%. Finally, the proposed method was applied to 31 real pig feed samples, detecting aflatoxins with concentrations between 0.2 and 3.2 ng/g.


Assuntos
Aflatoxinas , Micotoxinas , Animais , Suínos , Polímeros Molecularmente Impressos , Cromatografia Líquida de Alta Pressão , União Europeia
15.
Chemosphere ; 359: 142311, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38735500

RESUMO

Plastic is widely used in agricultural applications, but its waste has an adverse environmental impact and a long-term detrimental effect. The development of biodegradable plastics for agricultural use is increasing to mitigate plastic waste. The most commonly used biodegradable plastic is poly(butylene adipate co-terephthalate)/poly(lactic acid) (PBAT/PLA) polymer. In this study, an analytical procedure based on dispersive liquid-liquid microextraction (DLLME) followed by gas chromatography-mass spectrometry (GC-MS) in combination with chemometrics has been optimized to assess the degradation level of PBAT/PLA films by monitoring their characteristic degradation products. Carboxylic acids (benzoic, phthalic, adipic, heptanoic, and octadecanoic acids) and 1,4-butanediol have been found to be potential markers of PBAT/PLA degradation. The DLLME-GC-MS analytical approach has been applied for the first time to assess the degradation efficiency of several microorganisms used as degradation accelerators of PBAT/PLA based on the assigned potential markers. This analytical strategy has shown higher sensitivity and precision than standard techniques, such as elemental analysis, allowing us to detect low degradation levels.


Assuntos
Biodegradação Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Poliésteres , Poliésteres/química , Microextração em Fase Líquida/métodos , Plásticos Biodegradáveis/química , Polímeros/química , Ácidos Carboxílicos/química
16.
Chemosphere ; 341: 140141, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37696477

RESUMO

The presence and impacts of microplastics (MPs) are being extensively researched and reviewed, especially in the marine environment. However, mobility, transportation routes, and accumulation of leaching compounds such as additives in plastic waste including MPs are scarcely studied. Information regarding ecotoxicity and leachability of compounds related to MPs contamination in the environment is limited. Current work presents the levels of leachates from plastic materials in edible-root and non-edible root vegetables. Samples were analyzed by static headspace and gas chromatography-mass spectrometry (SHS-GC-MS) and the presence of 93 putative compounds was accurately monitored in the samples by the usage of Mass Spectrometry-Data Independent Analysis software. The application of chemometrics to the SHS-GC-MS dataset allowed differentiation between the levels of plastic related compounds in edible root and non-edible root vegetables, the former showing a higher content of plastic leachates. For SHS sampling, 3 g of the sample were incubated at 130 °C for 35 min in the HS vial and toluene and naphthalene were added as internal standards for quantification purposes. The developed SHS-GC-MS methodology is straightforward, reliable, and robust and allowed the quantification of sixteen plastic associated compounds in the samples studied in a range from 0.14 to 28800 ng g-1 corresponding to 2,4-di-tert-butylphenol and p,α-dimethylstyrene, respectively. Several of the quantified compounds pointed out to potential contamination of polystyrene and/or polyvinyl chloride MPs.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Microplásticos , Plásticos , Verduras/química , Cadeia Alimentar
17.
Foods ; 12(4)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36832898

RESUMO

The present work is focused on the development of an analytical platform to elucidate the metabolic pathway of PTSO from onion, an organosulfur compound well-known for its functional and technological properties and its potential application in animal and human nutrition. This analytical platform consisted of the use of gas chromatography-mass spectrometry (GC-MS) and ultra-high performance liquid chromatography quadrupole with time-of-flight MS (UHPLC-Q-TOF-MS) in order to monitor volatile and non-volatile compounds derived from the PTSO. For the extraction of the compounds of interest, two different sample treatments were developed: liquid-liquid extraction (LLE) and salting-out assisted liquid-liquid extraction (SALLE) for GC-MS and UHPLC-Q-TOF-MS analysis, respectively. Once the analytical platform was optimised and validated, an in vivo study was planned to elucidate PTSO metabolisation, revealing the presence of dipropyl disulfide (DPDS) in liver samples with concentrations between 0.11 and 0.61 µg g-1. The DPDS maximum concentration in the liver was observed at 0.5 h after the intake. DPDS was also present in all plasma samples with concentrations between 2.1 and 2.4 µg mL-1. In regard to PTSO, it was only found in plasma at times above 5 h (0.18 µg mL-1). Both PTSO and DPDS were excreted via urine 24 h after ingestion.

18.
Anal Bioanal Chem ; 404(3): 671-8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22526639

RESUMO

The optimization of a clean procedure based on ultrasound-assisted emulsification liquid-liquid microextraction for the sensitive determination of four bisphenols is presented. The miniaturized technique was coupled with gas chromatography-mass spectrometry after derivatization by in situ acetylation. The Taguchi experimental method, an orthogonal array design, was applied to find the optimal combination of seven factors (each factor at three levels) influencing the emulsification, extraction and collection efficiency, namely acetic anhydride volume, sodium phosphate concentration, carbon tetrachloride volume, aqueous sample volume, sodium chloride concentration and ultrasound power and application time. A second factorial design was applied with four factors and five levels for each factor, 25 experiments being performed in this instance. The matrix effect was evaluated, and it was concluded that sample quantification can be done by calibration with aqueous standards. The detection limits ranged from 0.01 to 0.03 ng mL(-1) depending on the compound. The environmentally friendly sample pretreatment procedure was applied to study the migration of the bisphenols from different types of samples: thermal printer paper, compact discs, digital versatile discs, small tight-fitting waistcoats, baby's bottles, baby bottle nipples of different materials and children's toys.

19.
Chemosphere ; 297: 134156, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35240154

RESUMO

The environment is threatened by the continuously increasing volume of plastic residue. Plastic recycling is an interesting alternative to mitigate this problem. However, recycled plastic products may have pollutants from their recycling process, collecting system and/or previous life which may hurt consumers health, thus making it key to authenticate and characterize recycled materials. An innovative non-targeted methodology by means of static headspace gas chromatography-mass spectrometry (SHS-GC-MS) has been developed to measure the volatile organic profile of virgin polyethylene terephthalate (PET) and with diverse content of recycled PET samples. A home-made MS database, with 161 organic compounds characteristics from plastic materials based on the literature, was made. Seventeen of those compounds were found in the studied samples and identified by matching their MS spectra with MS database libraries. These compounds are mainly aldehydes (pentanal, hexanal, heptanal, octanal, nonanal and decanal), and benzene derivatives (styrene, p-xylene, benzaldehyde, methylbenzene, and 1,2-dichlorobenzene) which we found to be the common in the samples of recycled PET. The combination of the dataset consisting in the peak area of the detected species by SHS-GC-MS and the use of chemometrics shown to be a valuable methodology for the discrimination between virgin PET samples and those with different recycled PET content based on their volatile profile. In addition, a novel strategy applying a statistical model based on partial least squares (PLS) regression was proposed, for the first time, to quantify the recycled plastic content in the PET samples.


Assuntos
Plásticos , Compostos Orgânicos Voláteis , Quimiometria , Cromatografia Gasosa-Espectrometria de Massas/métodos , Plásticos/química , Polietilenotereftalatos , Reciclagem , Compostos Orgânicos Voláteis/análise
20.
Chemosphere ; 286(Pt 1): 131588, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34293555

RESUMO

Non-targeted analysis for the monitoring of organic pollutants resulting from agricultural and industrial practices, plastics and pharmaceutical products of seawater from the Mar Menor lagoon (SE Spain) is proposed using dispersive liquid-liquid microextraction (DLLME) and gas chromatography-mass spectrometry (GC-MS). Initially, a home-made MS database including 118 environmental organic pollutants, whose presence in different ecosystems has already been reported, was created. The analytical method was applied for the analysis of 42 samples and a total of 18 pollutants were detected and identified. Samples were obtained from different sites around the Mar Menor in three sampling campaigns, enabling the assessment of impact of rain on the input of the detected chemicals and their distribution. In addition, this methodology was validated using a standard mixture containing 54 of the environmental pollutants included in the database, allowing the quantification of the 9 of the identified compounds (dibutyl phthalate, diisobutyl phthalate, diethyl phthalate, bis(2-ethylhexyl) phthalate, anthracene, 2-methylnaphthalene, hexachlorocyclopentadiene, bis(2-ethylhexyl) adipate and oleamide) with concentration between 3 and 271 µg L-1.


Assuntos
Poluentes Ambientais , Microextração em Fase Líquida , Ecossistema , Poluentes Ambientais/análise , Cromatografia Gasosa-Espectrometria de Massas , Água do Mar
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