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1.
J Agric Food Chem ; 67(36): 10174-10184, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31418563

RESUMO

The progress of lipid oxidation in foods is evaluated by measuring the peroxides and their scission products. However, hydrogen abstraction-independent pathways are not considered by commonly applied methods despite the known reactivity of epoxides toward biomolecules. Herein, a novel liquid chromatography tandem-mass spectrometry method was developed to detect hydroperoxidized and epoxidized triacylglycerols (TAGs) without derivatization or hydrolyzation of food samples. Epoxidized TAGs could be detected in refined canola oil at concentrations of 96.8 ± 2.08 µM, while only 5.77 ± 0.04 µM hydroperoxidized TAGs could be determined. In contrast to canola oil, margarine was more resistant to lipid oxidation since generation of epoxidized TAGs could only be marginally enhanced from 21.7 ± 0.48 to 28.8 ± 0.64 µM in margarine after treatment at 180 °C for 60 min, as also reflected by a peroxide value of 0.80 ± 0.00 mequiv O2/kg, which remained unchanged. The new method allows the assessment of food safety by the simultaneous measurement of hydroperoxidized and epoxidized TAGs without hydrolysis and laborious sample preparation.


Assuntos
Cromatografia Líquida/métodos , Margarina/análise , Espectrometria de Massas/métodos , Óleo de Brassica napus/química , Triglicerídeos/química , Compostos de Epóxi/química , Peróxido de Hidrogênio/química , Oxirredução
2.
Food Chem ; 301: 125216, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31404804

RESUMO

An improved liquid chromatography tandem mass spectrometry method is reported for the determination of residues of captan (+tetrahydrophthalimide), captafol, folpet (+phthalimide), and iprodione in fruits and vegetables. The optimized electrospray ionization parameters (high cone gas flow, and a low desolvation temperature) did not result in degradation of target compounds, rather they provided a significant advantage over the conventional GC-MS/MS methods, which lack sensitivity and repeatability. Strategies for minimizing losses in recovery of these compounds during sample preparation included cryogenic comminution, extraction with acidified ethyl acetate or acetonitrile, and dilution of the final extract with acidified water prior to LC-MS/MS analysis. The method performance complied with the SANTE/11813/2017 guidelines, with recoveries in the range of 70-120% at the LOQ of 0.01 mg/kg across the tested matrices at various pHs. The efficiency of the method was reflected in its precision (RSDs < 10%) for incurred residues.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Frutas/química , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Verduras/química , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/análise , Captana/análogos & derivados , Captana/análise , Cicloexenos/análise , Hidantoínas/análise , Limite de Detecção , Ftalimidas/análise
3.
Environ Pollut ; 253: 841-849, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349193

RESUMO

A rapid method based on solvent extraction followed by direct injection in liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) was developed for the targeted and suspect screening of contaminants in the soft tissues of the pearl oyster Pinctada imbricata radiata. The quantification method was first validated for the targeted analysis of 21 contaminants including some pharmaceutically active compounds, with the relative recoveries ranging from 88 to 123%, and method detection limits generally below 1 ng g-1 on the wet weight (ww) basis. This targeted analysis method was then applied to oyster samples collected around the Qatari coast between 2017/2018, and none of the 21 compounds were detected in these samples. The post-acquisition data treatment based on the accurate mass measurement in both full MS scan and All Ions MS/MS was further used for mining other contaminants in oyster extracts, as well as 21 targeted compounds spiked in oyster extracts (suspect screening). The 21 spiked compounds were identified successfully and the estimated limit of identification for the individual 21 compounds ranged from 0.5 to 117 ng g-1 ww of oyster tissues. A phthalate, di(2-ethylhexyl) phthalate (DEHP) was identified to be present in oyster extracts from 2018 batches, at a concentration level significantly higher than that in procedure blanks. These results confirmed that high resolution MS data obtained using the targeted method can be exploited through suspect screening workflows to identify contaminants in the tissues of bioindicator mollusks. However, a number of false identifications could be obtained and future work will be on improving the success rate of the correct identifications using this workflow.


Assuntos
Monitoramento Ambiental/métodos , Pinctada/metabolismo , Poluentes Químicos da Água/metabolismo , Animais , Cromatografia Líquida/métodos , Moluscos , Espectrometria de Massas em Tandem/métodos
4.
Food Chem ; 300: 125241, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31352289

RESUMO

In stock farming, illegal use of antipsychotics has caused the food safety problem. This paper presents for the first time, a multi-residues method for the simultaneous enantioselective determination of seven antipsychotics in pork, beef and lamb muscles. The behaviors of Chiralpak AGP toward changes in pH and organic modifier in mobile phase were studied, and all analytes were rapidly separated within 30 min. The calibration curves of all enantiomers were linear in the range of 1-250 ng g-1, with correlation coefficient above 0.9931. The recoveries of the targeted compounds were higher than 82.1%, with repeatability and intermediate precision lower than 18.2% and 17.4%, respectively. In three matrices, the limit of detection and limit of quantification ranged from 0.20 to 0.65 ng g-1 and from 0.40 to 1.00 ng g-1, respectively. The proposed method can be used to provide additional information for the reliable risk assessment of chiral antipsychotics.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Produtos da Carne/análise , Psicotrópicos/análise , Espectrometria de Massas em Tandem/métodos , Animais , Calibragem , Bovinos , Cromatografia de Fase Reversa/métodos , Análise de Alimentos/métodos , Limite de Detecção , Psicotrópicos/química , Reprodutibilidade dos Testes , Ovinos , Estereoisomerismo , Suínos
5.
Anal Bioanal Chem ; 411(23): 6129-6139, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31278554

RESUMO

Antibiotics may be present in agricultural soils through the application of organic amendments as fertilizers or by irrigation of fields with recycled water. As a result of these agricultural practices, antibiotics in soil can lead to their uptake by plants, entering in this way the food chain. Studies on the levels of antibiotics in cereal samples are scarce in the available literature. In this work, an analytical method was developed for the determination of 19 antibiotics (fluoroquinolones, sulfonamides, tetracyclines, and lincosamides) in four types of cereal grains (wheat, barley, rice, and oat). Ultrasound-assisted matrix solid-phase dispersion was selected as extraction technique with recoveries of target analytes ranging from 73 to 127% for the four cereals analyzed. Limits of quantification obtained ranged from 0.8 to 5.8 ng g-1. Compared with methods described for the analysis of antibiotics in cereals, the developed method uses a lower volume of extraction solvent and very good recoveries were obtained for all compounds. The validated method was applied to the analysis of different types of cereals samples, harvested from agricultural fields or purchased from local supermarkets. The analysis of the five cereal samples grown in fields with 3 years of consecutive organic amendments revealed that none of the nineteen antibiotics selected were found in any sample. Eleven commercial samples of cereals of different types and presentations were analyzed and enrofloxacin was detected in one rice sample; the presence of enrofloxacin in cereals or its incorporation into crops from soil or water not previously reported. Graphical abstract.


Assuntos
Antibacterianos/análise , Resíduos de Drogas/análise , Grão Comestível/química , Contaminação de Alimentos/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , Fluoroquinolonas/análise , Limite de Detecção , Lincosamidas/análise , Extração em Fase Sólida/métodos , Sulfonamidas/análise , Tetraciclinas/análise
6.
Anal Bioanal Chem ; 411(23): 6091-6100, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31289897

RESUMO

Two 600-bp DNA solutions (DNA600-G and DNA600-T) were developed as certified reference material, NMIJ CRM 6205-a, for the validation of DNA quantification methods. Both DNA600-G and DNA600-T are ideal as "spike-in control" because these materials have artificial nucleic acid sequences. The certified values were determined as the mass concentration of total DNA (whole DNA materials in sample solution regardless of sequence) at 25 °C by formic acid hydrolysis/liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) and inductively coupled plasma-mass spectrometry (ICP-MS) based on the amount of phosphorus. DNAs were synthesized, and plasmids including the synthesized DNAs were cloned into Escherichia coli DH5α. The amplified plasmids were digested with a restriction enzyme and highly purified. Then, the purified DNAs were diluted with water to approximately 1 ng/µL. By using the CRM-validated methods in fields where DNA quantification is required, the reliability of DNA quantification could be improved. Graphical abstract.


Assuntos
DNA/análise , Espectrometria de Massas/métodos , Sequência de Bases , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida de Alta Pressão/normas , Cromatografia Líquida/métodos , Cromatografia Líquida/normas , DNA/genética , Formiatos/química , Hidrólise , Espectrometria de Massas/normas , Plasmídeos/análise , Plasmídeos/genética , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/normas , Padrões de Referência
7.
Anal Bioanal Chem ; 411(23): 6173-6187, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31324926

RESUMO

A simple, rapid and efficient solid-phase extraction method based on synthesized carbon nanodots was developed for the preconcentration and extraction of personal care products and organophosphorus pesticides in environmental matrices. Factorial (screening) and central composite designs were employed for the optimization of experimental conditions that could potentially influence the percentage recoveries of the target analytes. The experimental variables, including sample pH, mass of adsorbent, eluent volume and sample volume, were examined. Under the optimized conditions, the developed method was validated, and acceptable analytical results obtained showed good performance. The method accuracy carried out at two spiking levels (10 and 100 µg L-1) in different sample matrices ranged between 63 and 120%. The method precision based on relative standard deviation (% RSD) was < 10%. The linear range studied had a determination coefficient of (R2 > 0.995). The limits of detection (LOD) and limit of quantification (LOQ) established varied between 0.015-0.125 and 0.05-0.415 µg L-1 ,respectively. The ensuing method was applied successfully in the determination of the five multi-class organic compounds under study, in influent and effluent wastewater matrices, sampled from a municipal wastewater treatment plant located in Pretoria, South Africa.


Assuntos
Carbono/química , Cosméticos/isolamento & purificação , Nanotubos/química , Compostos Organofosforados/isolamento & purificação , Praguicidas/isolamento & purificação , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação , Cromatografia Líquida/métodos , Limite de Detecção , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Purificação da Água/métodos
8.
J Chromatogr A ; 1603: 231-239, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31301796

RESUMO

A multiresidue method based on QuEChERS extraction followed liquid chromatography coupled with tandem mass spectrometry was developed and validated for the determination of 42 pesticides in marijuana. Less than 6 min is required for detection of all species. By using original QuEChERS, the sample preparation is also fast and simple. In the range from 1.0 to 50 µg kg-1, the coefficients of determination (r2) were greater than 0.980, and relative standard deviations for replicate injections were lower than 4.6%. The limit of detection (LOD) and limit of quantification (LOQ) were lower than 0.32 µg kg-1 and 1.07 µg kg-1, respectively. Precision and accuracy were verified through recovery of spiked samples at three distinct levels of concentration (1.0, 5.0, and 50.0 µg kg-1) in five replicates. Recovery values ranged from 82 to 119% with RSD lower than 6%. The method was applied to the detection of pesticide residues in six marijuana samples seized by the Police of Rio de Janeiro, Brazil, where imidacloprid, metazachlor, buprofezin, and metalaxyl were found in four of them.


Assuntos
Cannabis/química , Cromatografia Líquida/métodos , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Brasil , Limite de Detecção , Reprodutibilidade dos Testes , Fatores de Tempo
9.
Food Chem ; 299: 125146, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31302427

RESUMO

Matrix effects in complex tea matrices remains a great challenge to rapid quantitative analysis of multi-residue pesticides by analysis of mass spectrometry. Herein, a mixed-mode polymer cationic exchange based dispersive solid-phase extraction (DSPE) procedure was established to eliminate matrix effects of tea for a rapid target alkaline multi-residue pesticides analysis. One-step DSPE procedure can eliminate matrix interferences from the tea extract without additional dilution or tedious cleanup operations. Liquid chromatography-high resolution mass spectrometry using pre-column dilution injection mode was used as the detection technique, while eliminating solvent effects of target analytes and improving the detection sensitivity. Based on this effective analytical method, the results of absolute matrix effects were within 0.77-1.08 for quantitation of the 68 alkaline pesticides, and superior relative matrix effects were also achieved with RSD values below 9.8%. Finally, this method was validated and applied to the alkaline pesticides analysis of the 123 tea samples.


Assuntos
Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Extração em Fase Sólida/métodos , Chá/química , Cafeína/isolamento & purificação , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Resíduos de Praguicidas/química , Polifenóis/isolamento & purificação , Reprodutibilidade dos Testes
10.
Food Chem ; 299: 125136, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31302429

RESUMO

Glycerophospholipids (GPLs) constitute a chemical family within the saponifiable fraction of vegetable oils. GPLs have been scarcely studied in edible oils owing to the lack of sensitive and selective analytical methods. We have developed a method for identification, confirmation and relative quantitation of GPLs in vegetable oils. The method is based on solid-phase extraction (SPE) for isolation of GPLs and determination by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). As proof of concept, the approach has been applied to characterize GPLs in different olive oil categories, thus revealing compositional changes, which could be explained by factors such as the quality of fruits and the extraction process. Families such as glycerophosphatidic acids and phosphatidylglycerides are remarkable because of their capability to discriminate virgin olive oils from the rest of categories. These results open a door to additional studies targeted at the identification of olive oil quality by monitoring these lipids.


Assuntos
Cromatografia Líquida/métodos , Glicerofosfolipídeos/análise , Azeite de Oliva/química , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Análise de Alimentos/métodos , Glicerofosfolipídeos/isolamento & purificação , Óleos Vegetais/química
11.
Ecotoxicol Environ Saf ; 182: 109445, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31330408

RESUMO

In this study, a new, high-efficiency and sensitive method was determined to simultaneous analyze the residue of pyraclostrobin, picoxystrobin and its metabolite BF-500-3 in pepper fruit using modified QuEChERS pretreatment combined with ultra performance liquid chromatography-tandem mass spectrometry. The clean-up steps of QuEChERS procedure were optimized using the chemometric tools. Models of stepwise regression and surface response demonstrated that the optimal sorbent mixtures were 40 mg nano-zirconia + 10 mg C18 for pyraclostrobin and picoxystrobin and 30 mg nano-zirconia + 20 mg C18 for BF-500-3. The optimized purification procedures provided satisfactory recoveries for all tested fungicides with rates between 91% and 107% and relative standard deviations between 3.7% and 9.6%. The limits of detection and quantification were in the range of 0.0360-0.272 µg/kg and 0.120-0.910 µg/kg. Based on this method, the dissipation of pyraclostrobin, picoxystrobin and its metabolite in pepper fruit were determined under field conditions. Pyraclostrobin and picoxystrobin degraded rapidly with half-lives of 5.53-7.02 and 5.97-7.82 days and 5.09 and 5.68 days in 2016 and 2017, respectively. The residue levels of BF-500-3 increased first and then decreased. The terminal residues of all fungicides were below the maximum residue limits (MRLs). This research can not only provide guidance for the reasonable usage of pyraclostrobin and picoxystrobin in agriculture but also give a reference for the Chinese government to establish the MRL for pyraclostrobin in pepper.


Assuntos
Fungicidas Industriais/análise , Resíduos de Praguicidas/análise , Estrobilurinas/análise , Verduras/química , Agricultura , Cromatografia Líquida/métodos , Frutas/química , Espectrometria de Massas em Tandem/métodos
12.
Food Chem ; 300: 125188, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336274

RESUMO

An effective, simple and sensitive analytical method has been developed employing liquid chromatography coupled with tandem mass spectrometry and validated for estimation of five organophosphate pesticides at trace levels in six fruits and twelve vegetables. Plackett-Burman design and central composite design was used to screen and optimize the significant factors in modified QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. The method evaluation was done by matrix-matched calibration with linearity ranging from 5 to 500 µg/L with a correlation coefficient more than 0.990. The detection and quantification limit ranged from 0.1 to 1.0 µg/kg and 0.5 to 5 µg/kg, respectively. The mean recoveries were in the range of 76.89-110.30 % with the relative standard deviation less than 13.26% for all pesticides. Further, the method developed was applied to analyze real samples cultivated in the hill areas of Nilgiris, South India.


Assuntos
Fracionamento Químico/métodos , Contaminação de Alimentos/análise , Organofosfatos/análise , Praguicidas/análise , Calibragem , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Frutas/química , Índia , Análise Multivariada , Organofosfatos/isolamento & purificação , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Praguicidas/isolamento & purificação , Sensibilidade e Especificidade , Espectrometria de Massas em Tandem/métodos , Verduras/química
13.
J Chromatogr A ; 1603: 438-441, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31301799

RESUMO

The expansion of lithium ion battery (LIB) application is accompanied by the growth of battery pack sizes. This progression emphasizes the consideration of electrolyte safety as well as environmental aspects in case of abuse, accident, or recycling. Hexafluorophosphate is one of the most commonly used conducting salt anions in electrolytes. It has great potential to degrade to various acidic and non-acidic organo(fluoro)phosphates with presence of water and during battery cell operation. Consequently, toxicological investigation on these organo(fluoro)phosphates has emerged because they either have structural similarities as chemical warfare agents or play a widespread physiological role as phosphates in the human body. This circumstance underlines the need of isolated examination of these compounds for safety assessment. In this work, we used hydrophilic interaction liquid chromatography for the extraction of acidic organofluorophosphates from thermally aged LIB electrolytes. The developed two-step fractionation method provided high separation selectivity towards acidic head groups, which allowed the separation of undesired matrix and target compounds. These findings facilitate isolated toxicological investigations on organofluorophosphates that are beneficial for environmental and safety research, the battery cell industry, and human safety surveillance in regard to aged LIB electrolytes.


Assuntos
Cromatografia Líquida/métodos , Fontes de Energia Elétrica , Eletrólitos/química , Interações Hidrofóbicas e Hidrofílicas , Lítio/química , Organofluorfosfonatos/química , Humanos , Íons , Água
14.
J Chromatogr A ; 1603: 199-207, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31262516

RESUMO

Aryl organophosphate esters (aryl-OPEs) have gained increasing interest over the past few years since a growing number of emerging aryl-OPEs were identified in the environmental media. The currently available analytical methods for aryl-OPEs are usually tailored to detect a very limited number of aryl-OPEs and have inadequate sensitivity for several emerging aryl-OPEs. In this work, a comprehensive and sensitive method for the quantitative analysis of 17 aryl-OPEs in indoor dust samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated. The method allows for the determination of four traditional and thirteen emerging aryl-OPEs, which compose almost all the environmentally relevant aryl-OPEs that have been identified. For the first time, 2-isopropylphenyl diphenyl phosphate (2IPPDPP), 2,4-diisopropylphenyl diphenyl phosphate (24DIPPDPP), bis(2-isopropylphenyl) phenyl phosphate (B2IPPPP), bis(4-tert-butylphenyl) phenyl phosphate (B4tBPPP), and 2-naphthalenyl phosphate (NDPHP) were analyzed using LC-MS/MS. With a systematic optimization of the MS/MS parameters, chromatographic separation conditions, and sample preparation procedures, the target aryl-OPEs in the indoor dust were well separated within 13 min in one analytical run, with limits of quantification ranging from 0.09 to 3.2 ng g-1. Compared with the previously published methods, this method obtained a better sensitivity for most aryl-OPEs. The validated method was applied to 12 indoor dust samples that were collected from residential houses in Guangzhou, China. Both the traditional and emerging aryl-OPEs were frequently detected in the samples, except for NDPHP, with ∑aryl-OPEs ranging from 90 to 33,800 ng g-1. In particular, elevated concentrations of the newly identified tris(2,4-di-tert-butylphenyl) phosphate (AO168 = O) were observed in all the indoor dust samples. To our knowledge, these are the first reported data of AO168 = O levels in the environment media from China. These data indicate that AO168 = O is a ubiquitous pollutant that was previously overlooked and merits further investigation in the environment.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Cromatografia Líquida/métodos , Poeira/análise , Ésteres/análise , Organofosfatos/análise , Espectrometria de Massas em Tandem/métodos , Calibragem , China , Solventes
15.
J Chromatogr A ; 1603: 208-215, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31266645

RESUMO

In this paper, the benefits of using columns packed with particles of decreasing size (particle size gradient) in liquid chromatography was investigated from a theoretical point of view. It is indeed well known that such columns may be useful in gradient elution, since the decrease of particle size along the chromatographic column can provide extra peak focusing effect. In the present contribution, several parameters (i.e., mobile phase gradient steepness, retention times and operating pressures) were considered and the kinetic performance of various types of columns packed with particle size gradient were evaluated. In the best case, about 15-20% gain in efficiency can be expected at a given retention time when utilizing a particle size gradient, compared to constant particle size. Conversely, when fixing efficiency, the analysis time can be decreased by about 15% with an optimal particle size gradient. However, it is also important to keep in mind that a too large a particle size gradient can result in lower efficiencies than a column packed with monodisperse packing. We have introduced the gd value, which is a dimensionless measure of the particle size gradient steepness that measures the relative variation of particle diameter throughout the column with respect to the average. We finally observed that gd=0.3-0.4 provides the highest gain under practically useful conditions.


Assuntos
Cromatografia Líquida/métodos , Tamanho da Partícula , Cinética , Pressão
16.
Food Chem ; 300: 125175, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31323606

RESUMO

Despite the ban of nitrofurans (NFs) for use in food production in many countries in the 1990s, NF metabolites in food are still regularly detected during import control testing. We have developed a confirmatory routine method for the detection and quantification of NF metabolites in seafood using LC-MS/MS and validated the method according to the strict criteria in European legislation and Codex Alimentarius. Method characteristics were found to fulfill the criteria. We report for the first time a new false positive for 1-amino-2,4-imidazolidinedione (AHD), the metabolite of Nitrofurantoin (NFT). By using optimized washing procedures, the non tissue bound false positives can be minimized. The results from the validation on both lean and fatty fish and crustaceans, results from proficiency tests and routine use over many years, demonstrates that the method is fit for purpose to determine NF metabolites in the seafood category.


Assuntos
Cromatografia Líquida/métodos , Contaminação de Alimentos/análise , Nitrofurantoína/análise , Alimentos Marinhos/análise , Espectrometria de Massas em Tandem/métodos , Animais , Reações Falso-Positivas , Análise de Alimentos/métodos , Técnicas de Diluição do Indicador , Nitrofurantoína/metabolismo
17.
Food Chem ; 298: 125009, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260970

RESUMO

The objective of this study was to develop an accurate and fast method to determine malondialdehyde (MDA) levels in raw and processed meat. This method is based on extraction with trichloroacetic acid (TCA), reaction with 2-thiobarbituric acid (TBA) and quantification with ultraperformance liquid chromatography with a fluorescence detector (UPLC-FLD) with ʎexcitation = 530 nm and ʎemission = 550 nm and with a diode array detector (UPLC-DAD) with ʎabsorbance = 532 nm. The method tested was compared with the TBARS spectrophotometric method with ʎabsorbance = 532 nm. The concentration of MDA was similar for most of the matrices in both UPLC methods, except for cooked ham and frankfurter sausage. The TBARS spectrophotometric method overestimated the MDA concentration in all the matrices. Therefore, the use of both chromatographic methods, especially UPLC-FLD, to determine MDA would be more advisable than the classic TBARS method to avoid overestimation in meat and processed meat products.


Assuntos
Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Malondialdeído/análise , Produtos da Carne/análise , Animais , Fracionamento Químico/métodos , Cromatografia Líquida/instrumentação , Culinária , Fluorescência , Malondialdeído/isolamento & purificação , Carne/análise , Espectrofotometria/métodos , Suínos , Tiobarbitúricos/química , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Ácido Tricloroacético/química
18.
Food Chem ; 298: 125028, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260995

RESUMO

A robust and sensitive method utilising a hybrid ion chromatography tandem mass spectrometry system (IC-MS/MS) for the simultaneous determination of nine (9) highly polar anionic pesticides (chlorate, ethephon, fosetyl aluminium, glufosinate, glyphosate, N-acetyl AMPA, N-acetyl glyphosate, perchlorate and phosphonic acid) in fruit and vegetables is described. Mean recoveries (n = 6) at two fortification levels ranged from 83 to 112% with %CVs in the range 3-14%. The linearity range was 0.005-0.4 mg kg-1 and R2 values were >0.99 and the sensitivity of the method allowed (20× or 30×) dilution of samples. Provision of qualitative determination of aminomethylphosphonic acid (AMPA) was also facilitated via minor modification of the chromatographic conditions. Compliance with method validation criteria, survey results from the statutory UK/EU Pesticide Residues in Food 2018 programmes i.e. pea, pineapple, melon and successful z-scores for a UK proficiency testing scheme sample (ethephon in pineapple) demonstrate successful application of this IC-MS/MS method.


Assuntos
Contaminação de Alimentos/análise , Frutas/química , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Verduras/química , Ânions/análise , Ânions/química , Cromatografia Líquida/métodos , União Europeia , Análise de Alimentos/métodos , Limite de Detecção , Compostos Organofosforados , Resíduos de Praguicidas/química , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/instrumentação
19.
Gene ; 714: 143996, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31348980

RESUMO

The uniquely human α7-nAChR gene (CHRFAM7A) is evolved from the fusion of two partially duplicated genes, FAM7 and α7-nAChR gene (CHRNA7), and is inserted on same chromosome 15, 5' end of the CHRNA7 gene. Transcription of CHRFAM7A gene produces a 1256-bp open reading frame encoding dup-α7-nAChR, where a 27-aminoacid residues from FAM7 replaced the 146-aminoacid residues of the N-terminal extracellular ligand binding domain of α7-nAChR. In vitro, dup-α7-nAChR has been shown to form hetero-pentamer with α7-nAChR and dominant-negatively regulates the channel functions of α7-nAChR. However, the contribution of CHRFAM7A gene to the biology of α7-nAChR in the brain in vivo remains largely a matter of conjecture. CHRFAM7A transgenic mouse was created and differentially expressed proteins were profiled from the whole brain using iTRAQ-2D-LC-MS/MS proteomic technology. Proteins with a fold change of ≥1.2 or ≤0.83 and p < 0.05 were considered to be significant. Bioinformatics analysis showed that over-expression of the CHRFAM7A gene significantly modulated the proteins commonly involved in the signaling pathways of α7-nAChR-mediated neuropsychiatric disorders including Parkinson's disease, Alzheimer's disease, Huntington's disease, and alcoholism, suggesting that the CHRFAM7A gene contributes to the pathogenesis of neuropsychiatric disorders mostly likely through fine-tuning the functions of α7-nAChR in the brain.


Assuntos
Camundongos Transgênicos/genética , Receptor Nicotínico de Acetilcolina alfa7/genética , Animais , Encéfalo/metabolismo , Cromatografia Líquida/métodos , Cromossomos Humanos Par 15/genética , Perfilação da Expressão Gênica/métodos , Genes Duplicados/genética , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteômica/métodos , Transdução de Sinais/genética , Espectrometria de Massas em Tandem/métodos
20.
J Chromatogr A ; 1602: 350-358, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31257039

RESUMO

This work describes development of a quick and accurate online solid-phase extraction (SPE) liquid chromatography tandem mass spectrometry method for simultaneous determination of 87 emerging organic compounds, including 22 per- and polyfluoroalkyl substances, 58 pharmaceuticals and personal care products, and 7 organophosphorus flame retardants, in diverse water matrices. Considering the wide range of physicochemical properties for the target contaminants, efficient analysis in one injection is challenging. Thus, key extraction and analytical parameters, including online SPE sorbent, mobile phase additives, sample pH, loading solvent pH and composition, injection volume, and valve-switching time, were systematically optimized. The final conditions, namely a polymeric reversed-phase column with alkaline samples and an acidic loading solvent, provided satisfactory results for all target analytes compared to conventional methods that employ acidic samples for multi-residue analysis. The method detection limits (MDLs) ranged from 0.16 to 5.13 ng L-1 with 85% of MDLs lower than 2 ng L-1 for sample volumes of just 1.8 mL. The method also demonstrated satisfactory accuracy with 82% of analytes exhibiting 70-130% recovery. Importantly, only 30 min was required per sample. The optimized method was successfully applied to investigate the removal efficiency of emerging contaminants in a drinking water treatment plant and to analyze the environmental occurrence of target analytes. The method is sensitive, reliable, labor-saving, and cost effective, and therefore has the potential to advance large-scale environmental monitoring programs.


Assuntos
Cromatografia Líquida/métodos , Retardadores de Chama/análise , Fluorcarbonetos/análise , Produtos Domésticos/análise , Preparações Farmacêuticas/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Poluentes Químicos da Água/análise , Automação , Monitoramento Ambiental , Concentração de Íons de Hidrogênio , Internet , Limite de Detecção , Solventes/química , Fatores de Tempo
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