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1.
Anal Bioanal Chem ; 411(27): 7095-7104, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31673753

RESUMO

A candidate reference measurement procedure (RMP) based on isotope dilution coupled with liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) was developed and validated for the quantification of 17α-hydroxyprogesterone (17-OHP) in human plasma. 17-OHP spiked with a deuterium-labeled internal standard was extracted from plasma by liquid-liquid extraction with 1 mL n-hexane/ethyl acetate (3:2, v/v). Reversed-phase chromatography and positive electrospray ionization were used in the ID-LC-MS/MS. Gradient elution coupled with use of a C18-packed ultrahigh-performance liquid chromatography column allowed complete baseline resolution of 17-OHP from its structural analogue desoxycorticosterone in 6 min. To determine the 17-OHP level in human plasma, a bracketing calibration method was used to give higher accuracy and precision. The limit of detection and the lower limit of the measuring interval for the candidate RMP were 2.1 pg/mL (6.4 pmol/L) and 4.6 pg/mL (13.9 pmol/L), respectively. Extraction recovery was determined to be (96.08 ± 3.03)% (n = 3). Imprecision (intra-assay and interassay) was 4.03% or less at 0.83, 15.19, 64.22, and 313.46 ng/mL (2.51, 45.97, 194.34, and 948.56 nmol/L, respectively). Recoveries ranged from 98.05% to 102.24%. When comparing our RMP results with those obtained with an established RMP via International Federation of Clinical Chemistry and Laboratory Medicine external quality assessment scheme for reference laboratories in laboratory medicine (RELA) samples, we found that the biases ranged from -1.99% to 3.08% against the targets. No interference was observed, and the linear response ranged from 0.47 to 958.63 ng/mL (1.42 to 2900.90 nmol/L). Moreover, the candidate RMP was used to measure the concentration of 17-OHP in human plasma and was compared with an immunoassay using 40 plasma samples. The performance of the method meets the needs of an RMP (total coefficient of variation of 5% or less and bias of 3.08% or less). This method can be used for reference material value assignment of 17-OHP in human plasma matrix. It could also serve as an accurate reference baseline for routine methods to increase the accuracy and precision of certain clinical laboratory measurements. Graphical abstract Selected ion chromatograms obtained by liquid chromatography-tandem mass spectrometry with a C18 column for 17α-hydroxyprogesterone (17-OHP) from a plasma sample.


Assuntos
17-alfa-Hidroxiprogesterona/sangue , Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas em Tandem/métodos , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Deutério/sangue , Humanos , Técnicas de Diluição do Indicador , Marcação por Isótopo , Padrões de Referência , Valores de Referência , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/normas
2.
J Agric Food Chem ; 67(46): 12911-12917, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31647661

RESUMO

Tetrodotoxin and its analogues are the causative toxins of pufferfish poisoning. Tetrodotoxin has been recently detected in bivalve mollusks collected in New Zealand and Europe, highlighting the need to include tetrodotoxin in monitoring programs for bivalves by instrumental methods. In the present study, tetrodotoxin and its analogues in commercially available tetrodotoxin reagents were quantitated accurately by quantitative 1H-nuclear magnetic resonance (qNMR) spectroscopy. The results were applied to estimate relative molar responses of tetrodotoxin and its analogues in hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC/MS/MS). All four components (tetrodotoxin hemilactal form (1), tetrodotoxin 10,7-lactone form (2), 4-epitetrodotoxin (3), and 4,9-anhydrotetrodotoxin (4)) generated by equilibrating tetrodotoxin in aqueous solution were prepared as a mixture. From the HSQC spectrum of the mixture, the separated signals derived from three components, excluding 1, were selected and used for the quantitation. In addition, the relative molar responses of 3 and 4 on HILIC/MS/MS were calculated to be 0.73 and 0.46, respectively. These values could be useful for quantitation of 3 and 4 using the tetrodotoxin standard by HILIC/MS/MS. Our results also indicate that qNMR is useful for preparation of tetrodotoxin certified reference material.


Assuntos
Cromatografia Líquida/métodos , Espectroscopia de Ressonância Magnética/métodos , Toxinas Marinhas/química , Espectrometria de Massas em Tandem/métodos , Tetrodotoxina/química , Animais , Estrutura Molecular , Tetraodontiformes
3.
J Agric Food Chem ; 67(46): 12927-12935, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31657558

RESUMO

Emerging and fugitive contaminants (EFCs) released to our biosphere have caused a legacy and continuing threat to human and ecological health, contaminating air, water, and soil. Polluted media are closely linked to food security through plants, especially agricultural crops. However, measuring EFCs in plant tissues remains difficult, and high-throughput screening is a greater challenge. A novel rapid freeze-thaw/centrifugation extraction followed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis was developed for high-throughput quantification of 11 EFCs with diverse chemical properties, including estriol, codeine, oxazepam, 2,4-dinitrotoluene, 1,3,5-trinitroperhydro-1,3,5-triazine, bisphenol A, triclosan, caffeine, carbamazepine, lincomycin, and DEET, in three representative crops, corn, tomato, and wheat. The internal aqueous solution, i.e., sap, is liberated via a freeze/thaw cycle, and separated from macromolecules utilizing molecular weight cutoff membrane centrifugal filtration. Detection limits ranged from 0.01 µg L-1 to 2.0 µg L-1. Recoveries of spiked analytes in three species ranged from 83.7% to 109%. Developed methods can rapidly screen EFCs in agriculture crops and can assess pollutant distribution at contaminated sites and gain insight on EFCs transport in plants to assess transmembrane migration in vascular organisms. The findings contribute significantly to environmental research, food security, and human health, as it assesses the first step of potential entry into the food chain, that being transmembrane migration and plant uptake, the primary barrier between polluted waters or soils and our food.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Poluentes Ambientais/química , Lycopersicon esculentum/química , Extratos Vegetais/química , Espectrometria de Massas em Tandem/métodos , Triticum/química , Zea mays/química , Centrifugação , Poluentes Ambientais/isolamento & purificação , Filtração , Contaminação de Alimentos/análise , Química Verde/métodos , Ensaios de Triagem em Larga Escala/métodos , Extratos Vegetais/isolamento & purificação
4.
J Agric Food Chem ; 67(44): 12303-12312, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31597041

RESUMO

A new cinnamic acid derivative, (E)-3-[4-hydroxy-3-((E)-3-formyl-2-butenyl)phenyl]-2- propenoic acid (20) has been isolated from the ethanol extract of Brazilian green propolis along with three known cinnamic acid derivatives, 3,4-dihydroxy-5-prenyl-(E)-cinnamic acid (4), capillartemisin A (6), and 2,2-dimethylchromene-6-(E)-propenoic acid (8), and a flavonoid, dihydrokaempferide (16) by liquid-liquid participation, a series of column chromatography and preparative HPLC. Their structures have been determined by spectroscopic analyses and chemical synthesis of compound 20. The simultaneous quantification of 20 constituents, including 10 cinnamic acid derivatives, 7 flavonoids, and 3 caffeoylquinic acid derivatives, has also been developed and validated using LC-MS/MS. The new compound 20 was shown to activate PPAR α but not PPAR ß or γ.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cinamatos/química , Própole/química , Espectrometria de Massas em Tandem/métodos , Animais , Abelhas , Brasil , Cinamatos/síntese química , Cinamatos/isolamento & purificação
5.
Zhonghua Yan Ke Za Zhi ; 55(10): 769-776, 2019 Oct 11.
Artigo em Chinês | MEDLINE | ID: mdl-31607066

RESUMO

Objective: To identify differentially expressed proteins between the patients with proliferative diabetic retinopathy (PDR) and vitreous floaters, and explore treatment target for PDR based on isobaric tags for relative and absolute quantification (iTRAQ) LC-MS/MS Proteomics. Method: Vitreous samples were collected from 28 eyes of patients with PDR and 4 eyes with vitreous floaters, which served as controls. For quantitative proteomics, vitreous samples were combined and proteins extracted and labeled with iTRAQ peptide-tagging reagents. Samples were fractionated by liquid chromatography (LC), analyzed by tandem mass spectrometry (MS/MS) and Gene Ontology (GO) analyses performed on differentially expressed proteins identified in the PDR samples. Results: In the PDR vitreous, 26 proteins were identified that were differentially expressed when compared to the controls. Of these, 7 showed a significant increase (P<0.05) and 19 a significant decrease (P<0.05)in expression in PDR patients. These included some high abundance proteins including Retinoic acid receptor reactive protein 2 (PDR 1=85.0, PDR 2=83.0, Control 1=119.6, Control 2=120.2, FC=0.710, P=0.001), Semaphorin-4B(PDR 1=64.4, PDR 2=68.8, Control 1=135.4, Control 2=146.0, FC=0.473, P=0.023), Apolipoprotein B (PDR 1=104.4, PDR 2=106.6, Control 1=89.0, Control 2=85.3, FC=1.211, P=0.024), and Heat shock protein 70 (PDR 1=69.3, PDR 2=75.0, Control 1=137.7, Control 2=138.3, FC=0.523, P=0.026), which are closely related to the pathological mechanism of PDR. GO analysis clustered the differentially expressed genes into three major functional domains: Biological Processes, Molecular Function and Cellular Component. Differential gene expression was found in the categories of cellular metabolism, organonitrogen compound and carbohydrate derivative metabolic processes, transferase activity and transmembrane signaling receptor activity. KEGG Pathway analysis indicate that Chemerin signaling through Akt, Sema4B signaling via PI3K, and HIF-1α signal pathways were all altered in the PDR samples. Conclusions: In this study we identified variations in expression of genes extensively involved in key biological processes in the retina including neovascularization, cellular metabolism and transmembrane signaling, which provide new insights into the pathophysiology of PDR. Extracellular matrix was degraded and endothelial cell migration was induced by Chemerin, in addition, the destruction of blood-retinal barrier and neuronal apoptosis were induced by ApoB. Chemerin and ApoB accelerated the development of PDR. Sema 4B participated in vascular protection, HSP70 conducted anti-apoptosis. These two cytokines protected the retinal neurovascular in PDR patients. Therefore, Chemerin, Sema 4B, ApoB and HSP70 may be the treatment target for PDR. (Chin J Ophthalmol, 2019, 55:769-776).


Assuntos
Diabetes Mellitus Tipo 2/complicações , Retinopatia Diabética/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteoma/metabolismo , Proteômica/métodos , Corpo Vítreo/metabolismo , Biomarcadores/metabolismo , Estudos de Casos e Controles , Quimiocinas/metabolismo , Cromatografia Líquida/métodos , Diabetes Mellitus Tipo 2/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Proteoma/análise , Espectrometria de Massas em Tandem/métodos , Corpo Vítreo/química
6.
Anal Bioanal Chem ; 411(27): 7221-7231, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31583449

RESUMO

DNA methylation is a typical epigenetic phenomenon. Numerous methods for detecting global DNA methylation levels have been developed, among which LC-MS/MS has emerged as an excellent method from the viewpoint of sensitivity, reproducibility, and cost. However, LC-MS/MS methods have limitations due to a lack of the stability and the standardization required for a laboratory assay. The present study aimed to establish a robust assay that guarantees highly accurate measurements of global DNA methylation levels. There are at least three facets of the developed method. The first is discovery of the solvent conditions to minimize sodium adducts. The second is improvement of separation of nucleosides by LC using the columns that had not been used in previous similar studies. The third is success in reduction of the uncertainty of the measurement results, which was achieved by the calibration using the ratio of mdC but not the absolute amount in the presence of internal standards. These facets represent the advantage over methods reported previously. Our developed method enables quantification of DNA methylation with a short time length (8 min) for one analysis as well as with the high reproducibility of measurements that is represented by the inter-day CV% being less than 5%. In addition, data obtained from measuring global DNA methylation levels in cultured cell lines, with or without pharmacological demethylation, support its use for biomedical research. This assay is expected to allow us to conduct initial screening of epigenetic alterations or aberration in a variety of cells.


Assuntos
Metilação de DNA , DNA/química , Espectrometria de Massas em Tandem/métodos , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão/economia , Cromatografia Líquida de Alta Pressão/métodos , Citidina/análogos & derivados , Citidina/análise , Citidina/genética , DNA/genética , Humanos , Espectrometria de Massas em Tandem/economia , Fatores de Tempo
7.
J Agric Food Chem ; 67(42): 11591-11597, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31557017

RESUMO

A simple and eco-friendly dispersive solid-phase extraction method coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of the chiral pesticide tefluthrin in food and environmental samples. The response surface methodology was applied to optimize separation conditions. The elution order of tefluthrin enantiomers was Z-cis-(1S,3S)-(-)-tefluthrin and Z-cis-(1R,3R)-(+)-tefluthrin on a Lux Cellulose-1 chiral column was identified via a polarimeter and vibrating circular dichroism. The average recoveries in five matrices ranged from 76.9 to 107.6%, with intraday relative standard deviations (RSDs) less than 15.6% and interday RSDs less than 12.5% for two enantiomers. The enantioselective degradation was investigated via laboratory incubation experiments. Slightly enantioselective degradation was observed under aerobic conditions; (1S,3S)-tefluthrin degraded preferentially with the enantiomer fraction value of 0.57 at 120 days of incubation. No remarkable enantioselective degradation was observed under anaerobic and sterile conditions. It was the first time that pyrethroid pesticides were determined at the enantiomer levels via UPLC-MS/MS. This novel method was successfully applied for the enantioselective analysis of tefluthrin enantiomers in authentic samples, indicating its efficacy in investigating the environmental stereochemistry of tefluthrin in the food web and environment. It is of crucial importance to improve risk assessment and regulation of chiral pesticides in an agricultural system.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Ciclopropanos/química , Hidrocarbonetos Fluorados/química , Praguicidas/química , Poluentes do Solo/química , Solo/química , Espectrometria de Massas em Tandem/métodos , Estereoisomerismo
8.
J Agric Food Chem ; 67(41): 11481-11488, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31545895

RESUMO

Dry tea matrix contains an abundance of caffeine and polyphenols which are different from the food matrix (e.g., protein, lipid, and carbohydrates), and only a few studies have tried aflatoxins determination with tea samples. Here, a specific, accurate, and sensitive method was developed and validated for the simultaneous determination of aflatoxin B1, B2, G1, and G2 in dark teas. Aflatoxins were extracted by acetonitrile/water, press-filtered, and cleaned by multifunctional purification column (MFC) and immunoaffinity column (IAC) in tandem. The cleaned extract was analyzed by liquid chromatography tandem mass spectrometry. The matrix interference was effectively reduced by MFC-IAC cleaning method. Recoveries at the spiking concentrations of 5-60 µg/kg ranged from 77.5 to 93%, with relative standard deviations <11.0%. The correlation coefficients of aflatoxins standard were >0.998. The limits of detection were 0.024-0.21 µg/kg and the limits of quantification were 0.08-0.74 µg/kg. The intra- and interday accuracy ranged from 74 to 87%, and the intra- and interday precisions ranged from 0.4 to 3.1%. After the method validation, the aflatoxins contaminations in 100 collected dark teas were detected, and the results were compared with those of other methods.


Assuntos
Aflatoxinas/química , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Imunoensaio/métodos , Espectrometria de Massas em Tandem/métodos , Chá/química , Camellia sinensis/química , Folhas de Planta/química
9.
J Agric Food Chem ; 67(40): 11053-11065, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31525973

RESUMO

Oilseed rape (Brassica napus L.) is the second highest yielding oil crop worldwide. In addition to being used as an edible oil and a feed for livestock, rapeseed has high ornamental value. In this study, we identified and characterized the main floral major constituents, including phenolic acids and flavonoids components, in rapeseed accessions with different-colored petals. A total of 144 constituents were identified using ultrahigh-performance liquid chromatography-HESI-mass spectrometry (UPLC-HESI-MS/MS), 57 of which were confirmed and quantified using known standards and mainly contained phenolic acids, flavonoids, and glucosinolates compounds. Most of the epicatechin, quercetin, and isorhamnetin derivates were found in red and pink petals of B. napus, while kaempferol derivates were in yellow and pale white petals. Moreover, petal-specific compounds, including a putative hydroxycinnamic acid derivative, sinapoyl malate, 1-O-sinapoyl-ß-d-glucose, feruloyl glucose, naringenin-7-O-glucoside, cyanidin-3-glucoside, cyanidin-3,5-di-O-glucoside, petunidin-3-O-ß-glucopyranoside, isorhamnetin-3-O-glucoside, kaempferol-3-O-glucoside-7-O-glucoside, quercetin-3,4'-O-di-ß-glucopyranoside, quercetin-3-O-glucoside, and delphinidin-3-O-glucoside, might contribute to a variety of petal colors in B. napus. In addition, bound phenolics were tentatively identified and contained three abundant compounds (p-coumaric acid, ferulic acid, and 8-O-4'-diferulic acid). These results provide insight into the molecular mechanisms underlying petal color and suggest strategies for breeding rapeseed with a specific petal color in the future.


Assuntos
Brassica napus/química , Flores/química , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão/métodos , Cor , Ácidos Cumáricos/química , Flavonoides/química , Hidroxibenzoatos/química , Quempferóis/química , Espectrometria de Massas em Tandem/métodos
10.
J Agric Food Chem ; 67(40): 11256-11261, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31545583

RESUMO

Honey is a natural product that could be easily adulterated with various cheaper sweeteners. In the present study, matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was applied for the detection of honey adulteration based on oligosaccharide and polysaccharide profiles. MS-based strategy could reveal the presence of polysaccharides with higher degree of polymerization (DP ≥ 13) and abnormal trends of saccharides in adulterated honey samples, which could be used as indicators for the identification of honey adulteration with high-fructose corn syrup and corn syrup. MS/MS-based strategy was proposed to characterize the difference in the composition of oligosaccharide isomers between honey samples and adulterated ones with corn syrup or invert syrup, in which the [M+Cl]- of disaccharides, trisaccharides, and tetrasaccharides were fragmented to give diagnostic product ion pairs. The method is effective and robust for the high-throughput monitoring of honey adulteration, and provides a new perspective for the identification of other high-carbohydrate foods.


Assuntos
Contaminação de Alimentos/análise , Mel/análise , Oligossacarídeos/análise , Polissacarídeos/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Xarope de Milho Rico em Frutose/análise , Espectrometria de Massas em Tandem/métodos
11.
J Agric Food Chem ; 67(39): 10968-10976, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31487165

RESUMO

Food contact materials (FCMs) may release their chemical components into food and thus raise safety concerns. This paper attempted to study the presence of four major groups of FCM-related endocrine disruptors in fatty food: dialkyl phthalates, bisphenols, printing ink photoinitiators, and polyfluoroalkyl substances. All 41 target compounds were analyzed simultaneously by means of liquid chromatography coupled to tandem mass spectrometry. The sample preparation was significantly streamlined to reduce analysis costs by employing acetonitrile extraction, extract modification by water, and refrigeration at 5 °C. The new method was validated and applied to 60 real samples, including edible oils, butter, and chocolate, where 16 target compounds were measured at levels ≤13000 ng/g. The study also described the blank level increase and sensitivity loss caused by impurities present in the HPLC methanol solvent.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Espectrometria de Massas em Tandem/métodos , Compostos Benzidrílicos/análise , Fenóis/análise , Ácidos Ftálicos/análise
12.
J Agric Food Chem ; 67(39): 10977-10983, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31490679

RESUMO

In this study, an analytical method was developed and validated for simultaneous determination of five diamide insecticides (chlorantraniliprole, cyantraniliprole, flubendiamide, cyclaniliprole, and tetrachlorantraniliprole) in food matrices. Determination of the latter two diamide compounds is first reported. Samples were cleaned up by multiplug filters containing carbon nanotubes (CNT) or hydrophilic-lipophilic balanced copolymers (HLB) and classic dispersive solid phase extraction (d-SPE) procedures, respectively. The CNT multiplug filter performed the best in terms of process rapidity and cleanup efficiency; thus, it was finally chosen for sample cleanup. Instrumental analysis was completed in 5 min using ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Mean recoveries of the five diamides ranged from 84.3 to 110.0%, with intraday and interday relative standard deviations (RSD) of less than 13.5%. Limits of quantitation (LOQ) of all analytes ranged from 0.005 to 0.01 mg kg-1 in different matrices. The results indicate this method is reliable for monitoring the five diamide insecticides in various foods.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Diamida/química , Filtração/métodos , Contaminação de Alimentos/análise , Inseticidas/química , Resíduos de Praguicidas/química , Espectrometria de Massas em Tandem/métodos , Diamida/isolamento & purificação , Filtração/instrumentação , Inseticidas/isolamento & purificação , Nanotubos de Carbono/química , Resíduos de Praguicidas/isolamento & purificação
13.
J Agric Food Chem ; 67(38): 10800-10812, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31490681

RESUMO

In this work, a highly efficient pesticide residue screening and quantification method was established using ultrahigh-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry based on in-source fragmentation. Over 400 pesticides were tested, among which 96 pesticides displayed in-source fragmentation. A novel concept of in-source fragment fraction was proposed to evaluate the extent of in-source fragmentation, which was found to be chemical structure- and source parameter-dependent. A high-resolution MS/MS library containing 403 pesticides and 126 fragments was created and was applied for library searching of pesticide residues in vegetables and fruits. The introduction of in-source fragments effectively circumvented misannotation and occurrence of false negatives. The quantification ability for the fragments was validated in terms of recovery, linearity, and limit of quantification and its superiority to the parent pesticides was established. Finally, the proposed method was applied for the analysis of real samples and proficiency test samples, and false negative results were successfully avoided in the analysis.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Frutas/química , Resíduos de Praguicidas/química , Espectrometria de Massas em Tandem/métodos , Verduras/química , Contaminação de Alimentos/análise , Limite de Detecção
14.
J Agric Food Chem ; 67(38): 10791-10799, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31497956

RESUMO

Very weak signals of fragment ions of nosiheptide could be observed using liquid chromatography-tandem mass spectrometry. The preparation of 4-hydroxymethyl-3-methyl-1H-indole-2-carboxylic acid (HMIA), a specific fragment of nosiheptide, by alkaline hydrolysis is described. HMIA showed a good mass spectrometric signal in negative electrospray ionization mode. In the new method, the nosiheptide residue in muscle tissue was hydrolyzed with sodium hydroxide aqueous solution; this was followed by cleanup using mixed mode cartridges. Identification and quantification of nosiheptide were carried out by analyzing HMIA in hydrolysate of muscles. Nosiheptide showed a good linear relationship (r > 0.996) in the calibration range of 2-500 µg/kg, and a low limit of quantification of 2 µg/kg was obtained in swine, chicken, and fish muscles. Recoveries of nosiheptide from spiked muscle samples were 85-108% with relative standard deviations less than 10%. The proposed method was successfully applied for the detection of the nosiheptide residue in medicated animal tissues samples.


Assuntos
Antibacterianos/química , Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Drogas/química , Contaminação de Alimentos/análise , Carne/análise , Espectrometria de Massas em Tandem/métodos , Álcalis/química , Animais , Galinhas , Peixes , Hidrólise , Limite de Detecção , Músculos/química , Suínos , Tiazóis/química
15.
Anal Bioanal Chem ; 411(26): 6913-6929, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31418049

RESUMO

A method was developed for the analysis of 22 antiparasitic residues belonging to the benzoylurea, organophosphate, pyrimidinamine, pyrethrin and pyrethroid classes in salmon by liquid chromatography coupled with tandem mass spectrometry. Samples were extracted with acetonitrile-water as the extraction solvent with use of a vibrational shaking apparatus with a ceramic homogenizer. After extraction, the acetonitrile extracts were cleaned up by incubation at low temperature (-20 °C, 1 h) to remove fat, followed by dispersive solid-phase extraction using Z-Sep+ and primary-secondary amine as sorbents. Validation was performed following the 2002/657/EC and SANTE/11813/2017 guidelines. The trueness of the method ranged from 87% to 121% and precision ranged from 4.1% to 23.7%, with the exception of cyphenothrin, dicyclanil and azamethiphos. The method developed is particularly advantageous because the use of a vibrational shaker allows unattended extraction of samples and eliminates a laborious tissue disruption step, which increases sample throughput in the laboratory. The sample preparation and chromatographic separations can be performed in 5 and 4 h, respectively, for 36 samples. Graphical abstract.


Assuntos
Antiparasitários/análise , Praguicidas/análise , Alimentos Marinhos/análise , Animais , Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Drogas/análise , Peixes/metabolismo , Análise de Alimentos/métodos , Limite de Detecção , Resíduos de Praguicidas/análise , Salmão/metabolismo , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
16.
Anal Bioanal Chem ; 411(26): 6983-6994, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31463516

RESUMO

This study investigated the optimal inter-batch normalization method for gas chromatography/tandem mass spectrometry (GC/MS/MS)-based targeted metabolome analysis of rodent blood samples. The effect of centrifugal concentration on inter-batch variation was also investigated. Six serum samples prepared from a mouse and 2 quality control (QC) samples from pooled mouse serum were assigned to each batch, and the 3 batches were analyzed by GC/MS/MS at different days. The following inter-batch normalization methods were applied to metabolome data: QC-based methods with quadratic (QUAD)- or cubic spline (CS)-fitting, total signal intensity (TI)-based method, median signal intensity (MI)-based method, and isotope labeled internal standard (IS)-based method. We revealed that centrifugal concentration was a critical factor to cause inter-batch variation. Unexpectedly, neither the QC-based normalization methods nor the IS-based method was able to normalize inter-batch variation, though MI- or TI-based normalization methods were effective in normalizing inter-batch variation. For further validation, 6 disease model rat and 6 control rat plasma were evenly divided into 3 batches, and analyzed as different batches. Same as the results above, MI- or TI-based methods were able to normalize inter-batch variation. In particular, the data normalized by TI-based method showed similar metabolic profiles obtained from their intra-batch analysis. In conclusion, the TI-based normalization method is the most effective to normalize inter-batch variation for GC/MS/MS-based metabolome analysis. Graphical abstract.


Assuntos
Metaboloma , Metabolômica/métodos , Plasma/metabolismo , Soro/metabolismo , Animais , Centrifugação/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Masculino , Camundongos Endogâmicos ICR , Controle de Qualidade , Ratos , Síndrome da Serotonina/sangue , Síndrome da Serotonina/metabolismo , Espectrometria de Massas em Tandem/métodos
17.
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
18.
J Sci Food Agric ; 99(15): 6944-6953, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31414495

RESUMO

BACKGROUND: Dimethyl sulfide (DMS) is a small sulfur-containing impact odorant, imparting distinctive positive and / or negative characters to food and beverages. In white wine, the presence of DMS at perception threshold is considered to be a fault, contributing strong odors reminiscent of asparagus, cooked cabbage, and creamed corn. The source of DMS in wine has long been associated with S-methyl-l-methionine (SMM), a derivative of the amino acid methionine, which is thought to break down into DMS through chemical degradation, particularly during wine ageing. RESULTS: We developed and validated a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with a stable isotope dilution assay (SIDA) to measure SMM in grape juice and wine. The application of this new method for quantitating SMM, followed by the quantitation of DMS using headspace-solid phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS), confirmed that DMS can be produced in wine via the chemical breakdown of SMM to DMS, with greater degradation observed at 28 °C than at 14 °C. Further investigation into the role of grape juice and yeast strain on DMS formation revealed that the DMS produced from three different Sauvignon blanc grape juices, either from the SMM naturally present or SMM spiked at 50 mmol L-1 , was modulated depending on each of the four strains of Saccharomyces cerevisiae wine yeast used for fermentation. CONCLUSION: This study confirms the existence of a chemical pathway to the formation of DMS and reveals a yeast-mediated mechanism towards the formation of DMS from SMM during alcoholic fermentation. © 2019 Society of Chemical Industry.


Assuntos
Cromatografia Líquida/métodos , Sucos de Frutas e Vegetais/análise , Saccharomyces cerevisiae/metabolismo , Sulfetos/metabolismo , Espectrometria de Massas em Tandem/métodos , Vitamina U/análise , Vitis/química , Fermentação , Frutas/química , Frutas/metabolismo , Frutas/microbiologia , Sucos de Frutas e Vegetais/microbiologia , Odorantes/análise , Sulfetos/análise , Vitamina U/metabolismo , Vitis/metabolismo , Vitis/microbiologia , Vinho/análise
19.
Food Chem ; 301: 125285, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31387039

RESUMO

A method was developed and validated for determination of tryptoquialanines A and C in orange samples on epicarp (exterior peel), mesocarp (white peel), and endocarp (fruit juice) based on QuEChERS extraction and LC-MS/MS analysis. The method showed an excellent linearity over a range of 5-400 µg kg-1, with r2 ≥ 0.998. The limits of detection (LOD) and quantification (LOQ) were 5 and 10 µg kg-1, respectively. Recoveries showed values between 57 and 101%, with RSD ≤ 12%. Analysis of infected oranges showed diffusion of the alkaloids between the orange layers after 4 days post infection in concentrations > LOQ. Mycotoxin diffusion to healthy oranges after direct contact with infected oranges for 48 h, showed alkaloid concentrations ≥10 µg kg-1 on epicarp layer. The developed method can be easily applied for quality control in routine analysis of orange fruit due to the high risk that these tremorgenic alkaloids represent to human health.


Assuntos
Cromatografia Líquida/métodos , Citrus sinensis/microbiologia , Frutas/microbiologia , Penicillium/metabolismo , Espectrometria de Massas em Tandem/métodos , Citrus sinensis/química , Frutas/química , Limite de Detecção , Micotoxinas/análise
20.
Anal Bioanal Chem ; 411(25): 6697-6709, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31401670

RESUMO

The adulteration of meat products by the undeclared addition of commercially available blood plasma powder is quite conceivable due to low costs, high protein contents (about 70%), and advantageous functional properties. This applies particularly to pork, which has the highest meat production rate in the European Union. Evidence of this type of food fraud has been rather difficult to identify due to the lack of appropriate analytical methods, especially when adding plasma to meat of the same animal species. Consequently, a rapid UHPLC-MS/MS method for the detection of porcine blood plasma in emulsion-type pork sausages was developed. After protein extraction and tryptic digestion in a quick and simple one-pot process, species-specific marker peptides for porcine blood cell proteins (four markers) and plasma proteins (12 markers) were measured by UHPLC-MS/MS. Emulsion-type pork sausages were produced from a variety of raw materials that differed in the age or sex of the slaughtered pigs. Sausages were spiked with 0.5, 1, 1.5, 2, 3, or 5% meat substitution by one of two plasma powders, or produced as corresponding blank samples, and subjected to different thermal treatments as full or semi-preserves. Four plasma peptides were identified for the overall sample that allowed detection down to 0.7% meat substitution from the sum of their peak areas, with 5% error probability for both false positives and negatives.


Assuntos
Proteínas Sanguíneas/análise , Contaminação de Alimentos/análise , Produtos da Carne/análise , Carne Vermelha/análise , Animais , Cromatografia Líquida de Alta Pressão/economia , Cromatografia Líquida de Alta Pressão/métodos , Emulsões/química , Feminino , Análise de Alimentos/economia , Análise de Alimentos/métodos , Masculino , Peptídeos/análise , Plasma/química , Suínos , Espectrometria de Massas em Tandem/economia , Espectrometria de Massas em Tandem/métodos , Fatores de Tempo
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