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1.
Environ Monit Assess ; 192(11): 692, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-33037524

RESUMO

Residue levels of seven commonly used pesticides were determined in random samples of tomatoes, French beans, and kale collected from horticultural farms in Buuri, Imenti North, and Imenti South sub-counties in Meru, Kenya, just before delivery to the consumers. QuEChERS method for extraction followed by LC-MS/MS was used to determine the concentrations. The concentrations (µg kg-1 wet weight) in French beans, kale, and tomatoes ranged from below detection limit (BDL): BDL-48.65 (carbendazim), BDL-290.76 (imidacloprid), BDL-2.81 (acetamiprid), BDL-25.76 (azoxystrobin), BDL-105.18 (metalaxyl), BDL-0.15 (diazinon), and BDL-0.17(chlorpyrifos). The maximum residue levels determined in the horticultural produce from the three regions were 290 µg kg-1 for imidacloprid in tomatoes from Buuri and 25.76 µg kg-1for azoxystrobin in French beans from Imenti South. The pesticide residue levels generally were extremely low and met the MRLs set by EU and other countries, except for carbendazim and metalaxyl in French beans, and posed no concern to human health. The estimated daily intakes (EDI) (mg kg-1 BW/day) for the population of Meru County were very low ranging from 1.685 × 10-8 (acetamiprid) to 2.381 × 10-5 (imidacloprid) in tomatoes, 2.849 × 10-9 (metalaxyl) to 3.633 × 10-7 (azoxystrobin) in French beans, and 1.392 × 10-8 (diazinon) in kale, respectively. The health risk indices were subsequently extremely low for the detectable pesticide residues, ranging from 6.74 × 10-7 (acetamiprid) to 3.97 × 10-4 (imidacloprid) in tomatoes, 3.56 × 10-8 (metalaxyl) to 5.52 × 10-5 (chlorpyrifos) in French beans, and 6.96 × 10-5 (diazinon) in kale, respectively, indicating no health risk in the population, but their presence in these vegetables cannot be ignored as long-term exposure can still cause health risks.


Assuntos
Brassica , Lycopersicon esculentum , Resíduos de Praguicidas , Praguicidas , Cromatografia Líquida , Monitoramento Ambiental , Contaminação de Alimentos/análise , Humanos , Quênia , Resíduos de Praguicidas/análise , Praguicidas/análise , Espectrometria de Massas em Tandem
2.
Wei Sheng Yan Jiu ; 49(5): 809-814, 2020 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-33070828

RESUMO

OBJECTIVE: To establish a quantitative analysis method for sennoside A, sennoside B and physcion by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: The sample was extracted by methanol-2 mmol/L ammonium formate(9∶1) at 40 ℃ for 1 h. The separation was performed using Agilent Eclipse Plus C_(18 )(2. 1 mm × 50 mm, 1. 8 µm) column with gradient elution. The mobile phase was consisted of 0. 1% formic acid and methanol. Qualitative and quantitative analysis was conducted with an electrospray ionization source operated in the negative ionization(ESI~-) mode and multiple reaction monitoring(MRM) mode. RESULTS: The linear range of three compounds were from 0. 1 to 10 µg/mL with the correlation coefficients(r) above 0. 995. The spiked recoveries were in the range of 81. 9% to 114. 5% at the concentrations of 0. 02, 0. 15 and 1. 60 mg/g with relative standard devisions(RSDs) ranged from 0. 30% to 3. 43%(n=6). The detection limits of sennoside A and sennoside B were 1. 2 µg/g. The detection limit of physcion was 2. 4 µg/g. Sennoside A, sennoside B or physcion were detected in 19 out of 40 batches of samples. The content of sennoside A ranged from 0. 184 to 6. 33 mg/g and the content of sennoside B ranged from 0. 202 to 7. 23 mg/g. The content of physcion ranged from 0. 042 to 0. 79 mg/g. CONCLUSION: The method is simple, accurate and suitable for the determination of sennoside A, sennoside B and physcion.


Assuntos
Senosídeos , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Emodina/análogos & derivados
3.
Wei Sheng Yan Jiu ; 49(5): 829-867, 2020 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-33070831

RESUMO

OBJECTIVE: To establish an analytical method for determination of 20 kinds of ß-receptor blockers residues in animal foods by ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: The samples of animal foods were enzymatic hydrolysis by trichloroacetic acid(TCA), purified by MCX column. The separation was performed on a Waters ACQUITYTM BEH C_(18 )column(100 mm×2. 1 mm, 1. 7 µm), then the target compounds were detected by UPLC-MS/MS with ESI positive ion scan in mode of multiple reaction monitoring(MRM) and quantified by matrix matched external standard method. RESULTS: At the spiked level of 1, 2 and 4 µg/kg, the recoveries of each compound were in the range of 61. 9%-119. 1% with the relative standard deviations of 1. 5%-28. 4%(n=6). The qualitative limits of detections were 0. 01-0. 15 µg/kg and the quantitative limits were 0. 03-0. 50 µg/kg for the 20 targets compounds. By using the established method, the target compounds in 30 animal foods were detected, and no excessive veterinary drug residue were detected. CONCLUSION: The established method is simple, rapid, high sensitivity and good stability, with a wide variety and a certain development. It can provide more convenient and fast detection method support for the daily monitoring of veterinary drug residues in animal foods.


Assuntos
Contaminação de Alimentos , Espectrometria de Massas em Tandem , Ração Animal , Animais , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Contaminação de Alimentos/análise
4.
Chemosphere ; 258: 127387, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947680

RESUMO

It is well known that serum is an ideal and potential choice to reflect the toxicity of fluoride. However, the effects of fluoride on serum metabolome have not been reported until now. In this study, the models of 3-week-old rats exposed fluoride by breast milk and 11-week-old rats exposed fluoride via breast milk and drinking water containing sodium fluoride (100 mg/L) were established. Using Ultra Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (UPLC-MS/MS), as compared with control group, 28 negative (NEG) and 52 positive (POS) metabolites were significantly up-regulated, meanwhile 30 NEG and 21 POS significantly down-regulated metabolites were found in serum of 3-week-old rats exposed to fluoride. For 11-week-old fluorosis rats, there were 119 NEG and 65 POS metabolites significantly increased, and 7 NEG, 5 POS metabolites were obviously decreased. Importantly, nicotinamide, adenosine, 1-Oleoyl-sn-glycero-3-phosphocholine (OGPC), and 1-Stearoyl-sn-glycerol 3-phosphocholine (SGPC) were shared by two models. The metabolites of urea cycle, such as urea and N2-Acetyl-l-ornithine, betaine as a methyl donor, were regarded to reflect the fluorosis degree. These metabolites could be the potential markers of fluorosis, contributing to the prevention and treatment of fluorosis.


Assuntos
Fluoretos/toxicidade , Metaboloma/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Betaína , Cromatografia Líquida , Água Potável/química , Feminino , Humanos , Masculino , Metabolômica , Leite/metabolismo , Ratos , Fluoreto de Sódio , Espectrometria de Massas em Tandem
5.
Chemosphere ; 254: 126872, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957284

RESUMO

The distribution of 20 personal care products (PCPs), including seven preservatives, six UV filters, five anticorrosion agents, and two antimicrobials, were determined in 40 swimming pools using solid phase extraction followed by liquid chromatography-tandem mass spectrometry. Among 14 targets detected, 1H-benzotriazole and triclocarban were observed in all samples. The detected concentrations of preservatives, UV filters, anticorrosion agents, and antimicrobials were in the ranges of not detected (nd)-179 ng L-1, nd-289 ng L-1, nd-58.4 ng L-1, and nd-56.9 ng L-1, respectively. The presence of preservatives, UV filters and antimicrobials in pool waters might be mainly brought in by human activities while anticorrosion agents were mainly from the source water. Furthermore, the concentrations of methylparaben, ethylparaben, 1H-benzotriazole, 5-methyl-1H-benzotriazole, 5-chloro-1H-benzotriazole, and 5,6-dimethyl-1H-benzotriazole in indoor pools were found higher than those in outdoor pools. The longer opening time and weaker light intensity for indoor pools might cause the difference. The redundancy analysis showed significantly negative correlations between the concentrations of parabens and the contents of residual chlorine in the pool waters. A higher chlorine residue may promote the decomposition of parabens. Health risk assessment showed that skin penetration would be the main approach for the intake of PCPs by swimmers while swimming. Compared with the non-athletic swimmers, the athletic swimmers might be more sensitive, but the health risks for both groups of swimmers could be negligible.


Assuntos
Cosméticos/análise , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Carbanilidas , Cloro/análise , Cromatografia Líquida , Humanos , Parabenos , Medição de Risco , Extração em Fase Sólida , Natação , Piscinas , Triazóis
6.
Sci Total Environ ; 740: 139696, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32927529

RESUMO

China has the world's largest burden of Hepatitis B virus (HBV) infection, with 86 million HBV carriers, including 32 million chronic Hepatitis B patients. To monitor the HBV prevalence in near real-time, a wastewater-based epidemiology (WBE) method by using lamivudine as a biomarker was conducted in 19 cities in the Southern part of China. LC-MS/MS was utilized to quantify lamivudine in sewage, and satisfactory method validation results were achieved. The average concentration of lamivudine in sewage was 156.4 ±â€¯107.1 ng/L, and the daily consumption was 30.1 ±â€¯19.8 mg/day/1000inh in average ranging from 0.4 to 105.5 mg/day/1000inh. The prevalence of chronic Hepatitis B was estimated to be 2.5% ±â€¯1.7% based on the prevalence of lamivudine usage, which was 0.035% ±â€¯0.023%. Besides, the estimated HBV prevalence in population aged over 15 years in 19 cities was 6.8% ±â€¯4.5% and was consistent with the previous statistical data of 7% in 2018. This research demonstrated that the estimation of HBV prevalence by WBE with lamivudine as a biomarker is feasible in big cities in Southern China.


Assuntos
Antivirais , Vírus da Hepatite B , Adolescente , China , Cromatografia Líquida , Cidades , Hepatite B , Vírus da Hepatite B/isolamento & purificação , Humanos , Prevalência , Espectrometria de Massas em Tandem , Vigilância Epidemiológica Baseada em Águas Residuárias
7.
Zhongguo Zhong Yao Za Zhi ; 45(15): 3726-3739, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893565

RESUMO

This study is to explore the effect of Qingfei Paidu Decoction(QPD) on the host metabolism and gut microbiome of rats with metabolomics and 16 S rDNA sequencing. Based on 16 S rDNA sequencing of gut microbiome and metabolomics(GC-MS and LC-MS/MS), we systematically studied the serum metabolites profile and gut microbiota composition of rats treated with QPD for continued 5 days by oral gavage. A total of 23 and 43 differential metabolites were identified based on QPD with GC-MS and LC-MS/MS, respectively. The involved metabolic pathways of these differential metabolites included glycerophospholipid metabolism, linoleic acid metabolism, TCA cycle and pyruvate metabolism. Meanwhile, we found that QPD significantly regulated the composition of gut microbiota in rats, such as enriched Romboutsia, Turicibacter, and Clostridium_sensu_stricto_1, and decreased norank_f_Lachnospiraceae. Our current study indicated that short-term intervention of QPD could significantly regulate the host metabolism and gut microbiota composition of rats dose-dependently, suggesting that the clinical efficacy of QPD may be related with the regulation on host metabolism and gut microbiome.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Animais , Bactérias/classificação , Cromatografia Líquida , Metabolômica , Ratos , Espectrometria de Massas em Tandem
8.
Zhongguo Zhong Yao Za Zhi ; 45(16): 3826-3836, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893577

RESUMO

Magnolia officinalis is a traditional Chinese medicine,with many years of cultivating process, M. officinalis leaves show more differentiation types due to the exchange of seeds from different provenances. "Da Ao"(DA), "Xiao Ao"(XA), "Chuan Hou"(CH),and "Liu Ye"(LY)are the main types of M. officinalis in Sichuan province of China,and there were obvious differences in growth rate,chemical composition,leaf shape and leaf colour. This study selected different types of M. officinalis leaves(DA,XA,LY and CH)from Sichuan to determine their chlorophyll content. Transcriptomic level sequencing of different types of M. officinalis leaf tissues was by high-throughput sequencing analysis and proteomics used an integrated approach involving TMT labelling and LC-MS/MS to quantify the dynamic changes of the whole proteome of M. officinalis. The results showed that CH had the lowest chlorophyll content while DA had the highest chlorophyll content. Furthermore,transcriptome and proteomics results showed that chlorophyll synthesis pathway in DA glutamine-tRNA reductase,urinary porphyrins decarboxylase(UROD),oxygen-dependent protoporphyrin(ODCO),the original-Ⅲ oxidase protoporphyrin oxidase(PPO),magnesium chelating enzyme subunit ChlD,protoporphyrin magnesium Ⅸ monomethyl ester [oxidative] cyclase(MPPMC)were significantly higher than CH,XA and LY,consistent in the results of determination of chlorophyll content(chlorophyll content was highest of 37.56 mg·g~(-1) FW). Some rate-limiting enzymes related to the chlorophyll synthesis,such as ODCO,PPO and MPPMC were tested by Parallel Reaction Monitoring(PRM),and the results showed that the rate-limiting enzyme content in DA was higher than that in other three types. Therefore,based on the differences in leaf color of four types of M. officinalis,the research conducted a preliminary study on the chlorophyll metabolism pathway in leaves of different types of M. officinalis,and explored relevant genes and proteins causing leaf color differences from the molecular level,so as to lay a foundation for studying the differences in growth and development of different types of M. officinalis.


Assuntos
Magnolia , China , Clorofila , Cromatografia Líquida , Folhas de Planta , Proteoma , Espectrometria de Massas em Tandem , Transcriptoma
9.
Zhongguo Zhong Yao Za Zhi ; 45(16): 3908-3914, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893588

RESUMO

G-quadruplex DNA has become an important target for tumor therapy and anti-tumor development. Modern pharmacology has proved that Macleaya cordata has anti-inflammatory, antibacterial, anti-tumor and other pharmacological effects. Affinity ultrafiltration method can screen active ingredients from compounds rapidly, but G-quadruplex DNA ligands are difficult to dissociate, which is a key step in conventional ultrafiltration method. In this paper, the filtrates after ultrafiltration were determined by HPLC-MS in substitution. The peaks with 20% reduction of MS response from the incubation vs control were considered to be ligand components to G-quadruplex. Two of the peaks with the relative abundance above 30% were identified as sanguinarine(SAN) and chelerine(CHE). Their circular dichroism conformations further proved that SAN and CHE are active ligands of HT4. In addition, another two gradients with high relative abundance were identified as protopine(PRO) and allpcryprotopine(ALL). The binding rate of SAN, CHE, PRO and ALL was calculated according to the HPLC-MS results, and the results showed a consistency with that of the molecular docking method. The proposed method can be used to screen active components from mixture.


Assuntos
Quadruplex G , Ultrafiltração , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Ligantes , Espectrometria de Massas , Simulação de Acoplamento Molecular
10.
Wei Sheng Yan Jiu ; 49(4): 564-568, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928346

RESUMO

OBJECTIVE: In order to investigate the effect of yeast on reducing mycotoxin damage in dried fish. METHODS: A strain of Meyerozyma guilliermondii MH 211588. 1(MG-81) was mixed and fermented 48 h with dried Lutjanus erythopterus which contaminated aflatoxin B_1(AFB_1) and T-2 toxin(T-2). The toxin concentration in fermentation at different time was detected by LC-MS/MS, and fermentation was fed with mice by intragastric administration(7 d). Blood routine and four liver function enzymes were measured by hematology analyzer and microplate spectrophotometer respectively. The elimination effect of MG-81 isolate on mycotoxin damage in dried fish was evaluated by the toxin concentration at different time and its toxic effect on mice. RESULTS: The removal rates of AFB_1 and T-2 in dried fish fermentation showed a parabolic linear growth trend with the prolongation of fermentation time. The removal rates of AFB_1 and T-2 in dried fish fermentation broth tended to be stable at 36 h(the removal rates of AFB_1 and T-2 were 83. 7%±1. 3% and 78. 5%±0. 8%). This indicated that 36 h was the optimal time for MG-81 to remove mycotoxins in dried fish. At the same time, it was found that there was no significant change in the indexes of MG-81 dried fish fermentation compared with the control group(P>0. 05), while the same dose of AFB_1 and T-2 dried fish fermentation(without MG-81), the leucocytes, lymphocytes, erythrocyte, hemoglobin, platelet and mean platelet volume of mice were significantly lower than those of control group(P>0. 05), showing obvious hemotoxicity and immunotoxicity. The activity of four liver enzymes was increased significantly(P<0. 05), showing obvious hepatotoxicity. CONCLUSION: The fermentation of MG-81 for 36 h can effectively remove AFB_1 and T-2 from dried fish and eliminate their hazards.


Assuntos
Saccharomycetales , Toxina T-2 , Aflatoxina B1/análise , Animais , Cromatografia Líquida , Camundongos , Espectrometria de Massas em Tandem
11.
Wei Sheng Yan Jiu ; 49(4): 591-602, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928350

RESUMO

OBJECTIVE: To establish an analytical method for determination of 6 kinds of α_2-agonists in animal foods by ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: The samples of animal food were enzymatic hydrolysis by ß-glucosidase/arylsulfatase, purified by MCX column. The separation was performed on a Dikma leapsil C_(18) column(2. 1 mm×100 mm, 2. 7 µm), then the target compound were detected by ultra high performance liquid chromatography-tandem mass spectrometry with electron spray ionization(ESI) positive ion scan in mode of multiple reaction monitoring(MRM) and quantified by matrix matched external standard method. RESULTS: At the spiked level of 1, 2 and 4 µg/kg, the recoveries of each compound were in the range of 70. 4%-111. 2% with the relative standard deviations of 2. 3%-18. 8%. The qualitative limits of detections were 0. 06-0. 3 µg/kg and the quantitative limits were 0. 2-1. 0 µg/kg for the 6 targets compounds. By using the established method, the target compound in 30 samples including pork, pig liver, pig kidney, beef and mutton were detected, and no excessive veterinary drug residue were detected. CONCLUSION: The established method is simple, rapid, high sensitivity and good stability, with a wide variety and a certain development. It can provide more convenient and fast detection method support for the daily monitoring of veterinary drug residues in animal food.


Assuntos
Resíduos de Drogas/análise , Espectrometria de Massas em Tandem , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Contaminação de Alimentos/análise , Suínos
12.
Wei Sheng Yan Jiu ; 49(4): 597-602, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928351

RESUMO

OBJECTIVE: To establish a method for analysis of 25-hydroxylvitamin D_2(25(OH)D_2), 25-hydroxylvitamin D_3(25(OH)D_3)and vitamin K_1 in serum by ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS), which can be applied in diagnosis of vitamin deficiency and estimation on the nutritional status of people. METHODS: Serum samples mixed with d_6-25(OH)D_3, d_7-vitamin K_1(internal standard)were precipitated with acetonitrile and extracted with n-hexane. The sample solution was separated using BEH C_(18) column(2. 1 mm×100 mm, 1. 7 µm) with gradient elution using methanol-water containing 0. 1% formic acid as mobile phase. The target molecule was detected in positive electrospray ionization(ESI~+) and multiple reaction monitoring. RESULTS: The concentration of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 showed good linearity in the range 5. 0-75. 0 ng/mL, 2. 0-81. 5 ng/mL and 0. 3-12. 0 ng/mL, respectively, with the correlation coefficients greater than 0. 995. The limits of detection(LOD) of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 were 1, 0. 25 and 0. 1 ng/mL, and the limits of quantification(LOQ) for 25(OH)D_2, 25(OH)D_3 and vitamin K_1were 3, 0. 75 and 0. 3 ng/mL, respectively. The recoveries of three levels in the matrix were 98. 5%-104. 3%, the relative standard deviation(RSD) were all less than 5. 0%(n=6). CONCLUSION: An UPLC-MS/MS method for analysis of 25(OH)D_2, 25(OH)D_3 and vitamin K_1 in serum is sensitive, rapid, accurate and suitable for the nutritional surveillance of vitamin D and K_1 in the population.


Assuntos
Espectrometria de Massas em Tandem , Vitamina K 1 , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Vitamina D/análogos & derivados
13.
J Chromatogr A ; 1628: 461442, 2020 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-32822981

RESUMO

An analytical method for the quantification of thirty-three perfluoroalkyl and polyfluoroalkyl substances (PFASs) in animal liver was developed applying the isotopic dilution methodology with twenty-one labelled isotopologues of native compounds. The proposed protocol involved the determination of short and long aliphatic chain PFASs (C4C18) extracting liver with acetonitrile followed by two clean-up steps. The instrumental analysis was performed with liquid chromatography coupled to high-resolution mass spectrometry. The acquisition method combined full MS/dd-MS2, t-SIM/dd-MS2 and SIM experiments with variable resolution in order to maximize in one chromatographic run accuracy, sensitivity and selectivity. An eight-level validation study was performed evaluating linearity, trueness, precision, quantification and detection limits. Trueness was from 94 to 126% with intra-laboratory reproducibility lower than 20%. Limits of quantification were in the range 2-100 pg g-1, except for 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy)-propanoic acid, HFPO-DA (500 pg g-1). The analysis of a certified reference material (IRMM-427) and participation in a proficiency test scheme (FAPAS - 0687) confirmed these satisfactory performances. Finally, the application of the developed procedure to detect PFASs in sixteen liver samples of farm animals revealed that chicken was the less contaminated species.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Fluorcarbonetos/análise , Fígado/química , Espectrometria de Massas em Tandem , Animais , Reprodutibilidade dos Testes
14.
J Chromatogr A ; 1628: 461447, 2020 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-32822986

RESUMO

Waterfowl populations have been decreasing in Europe for the last years and pollution appears to be one of the main factors. This study was conducted to develop a single sensitive and robust analytical method for the monitoring of 2 fungicides, 15 herbicides, 3 insecticides and 24 transformation products in wild bird eggs. One of the major challenges addressed was the characterization of chemicals with large logP range (from -1.9 to 4.8). A total of 11 different extraction parameters were tested in triplicate to optimize the extraction protocol, on generic parameters, buffer addition and use of clean-up steps. Quantification was based on matrix-match approach with hen eggs as reference matrix (34 analytes with r²>0.99). Particular attention was payed to matrix effects (-28% on average), quantification limits (0.5 to 25 ng.g-1 dry mass / 0.2 to 7.5 ng.g-1 fresh mass) and extraction yields (46 to 87% with 25 analytes up to 70%) to ensure the relevance of the method and its compatibility with ultra-trace analysis. It led to a simple solid/liquid low temperature partitioning extraction method followed by LC-MS/MS. Analysis of 29 field samples from 3 waterfowl species revealed that eggs were slightly contaminated with pesticides as only one egg presented a contamination (terbutryn, herbicide, 0.7 ng.g-1) and confirmed the relevance of the method.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida , Ovos/análise , Praguicidas/análise , Espectrometria de Massas em Tandem , Animais , Aves , Poluentes Ambientais/análise , Europa (Continente) , Praguicidas/química
15.
J Chromatogr A ; 1626: 461339, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797821

RESUMO

We report on a systematic and comprehensive (0.7 ≤ k'' ≤ 122) experimental study of the effect of the zone retention factor k'' on eddy dispersion (heddy) in packed bed columns for liquid chromatography. The values for heddy are obtained by subtracting rigorously estimated contributions to the total plate height from longitudinal diffusion (hB) and the mobile (hCm) and stationary zone (hCs) mass transfer resistances. For the first time, hCm-values are calculated using an expression for the Sherwood number (Sh) that has been established and validated in the relevant velocity range. Experiments were carried out on both a fully-porous and a core-shell particle column. In both cases, the eddy dispersion systematically decreased with increasing retention factor k'', dropping 0.5 to 0.8 reduced plate height units when going from the lowest to the highest k''. To establish a simple empirical fitting equation that can represent the observed effects, the widely used power law-based Knox model has been extended to express the dependence of its A- and n-parameters on the retention factor.


Assuntos
Cromatografia Líquida/métodos , Algoritmos , Cromatografia Líquida/instrumentação , Difusão , Tamanho da Partícula , Porosidade
16.
J Chromatogr A ; 1626: 461345, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797825

RESUMO

Modern liquid-liquid chromatography mainly refers to the following two kinds of chromatographic apparatuses: countercurrent chromatography based on hydrodynamic equilibrium systems and centrifugal partition chromatography based on hydrostatic equilibrium systems. In this paper, the recent advancements in enantioseparations by liquid-liquid chromatography, including the separation mechanism, chiral selector, two-phase solvent system, methods to improve the peak resolution and recent applications, are reviewed. The future outlook for liquid-liquid chromatography in enantioseparations is also proposed.


Assuntos
Cromatografia Líquida/métodos , Algoritmos , Distribuição Contracorrente , Concentração de Íons de Hidrogênio , Ligantes , Solventes/química , Estereoisomerismo
17.
J Chromatogr A ; 1626: 461353, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797833

RESUMO

This paper reports the development of an LC-ESI-MS2 method for the sensitive determination of hydroxylated polychlorinated biphenyls (OH-PCBs) in human serum samples. Congener-specific separation was achieved by using a polar-embedded stationary phase, previously optimized for the working group, which provided better separation of isobaric compounds than the common octadecylsilane phases. MS fragmentation patterns and energies showed differences among OH-PCB congeners, mainly depending on the position of OH-group and the number of chlorine atoms in the molecule, although the most intense transitions were always those corresponding to the neutral loss of an HCl group from the quasi-molecular ion cluster. The method allowed the determination of OH-PCBs with good linearity (dynamic linear range of four orders of magnitude with R2 higher than 0.995) and precision (relative standard deviations of absolute areas lower than 10%), and with better sensitivity than other similar methods previously described in the literature. Matrix effect has been evaluated and reduced to less than 10% by the addition of isotopically labeled standards and a 10-fold dilution of the final sample extract. The low iLODs provided by the developed method (from 1.2 to 5.4 fg µL-1 for all the OH-PCBs studied, except 4'-OHCB108, whose iLOD was 61 fg µL-1) allows dilution without losses of detected peaks. Finally, the applicability of the method has been demonstrated by analyzing human serum samples belonging to an interlaboratory exercise.


Assuntos
Cromatografia Líquida/métodos , Cromatografia de Fase Reversa/métodos , Bifenilos Policlorados/análise , Espectrometria de Massas em Tandem/métodos , Humanos , Hidroxilação , Bifenilos Policlorados/sangue , Bifenilos Policlorados/química , Espectrometria de Massas por Ionização por Electrospray
18.
Zhonghua Xin Xue Guan Bing Za Zhi ; 48(6): 507-512, 2020 Jun 24.
Artigo em Chinês | MEDLINE | ID: mdl-32842262

RESUMO

Objective: To develope and validate a reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of vardenafil concentration in plasma of rat. Methods: Plasma samples of normal Sprague-Dawley rats were collected. A Phenomenex Synergi Polar-RP 80A column (2.0 mm×50 mm, 4 µm) was used. Column temperature was set at 30 ℃. Mobile phase A was 0.1% formic acid in water; mobile phase B was 0.1% formic acid in acetonitrile. The flow rate was 0.4 ml/minutes. Quantitative determination was performed by electrospray ionization, operating in positive ion multiple reaction monitoring (MRM) mode. Cisapride was used as the internal standard. The feasibility of the method was evaluated by examining its specificity, linearity and quantitative range, precision and accuracy, matrix effects, and stability. Results: Under the selected chromatographic and mass spectrometry conditions, the monitoring ions of vardenafil and internal standard were mass-to-charge ratio(m/z) 489.3/151.2 and 466.4/234.2, the retention times of vardenafil and internal standard were 2.62 and 2.80 minutes, respectively, and the peak shape was satisfactory. The method has good linearity in the concentration range of 0.2-200 ng/ml. The intra-batch precision (%CV) and accuracy (%DEV) of vardenafil were 1.5%-9.7% and -6.8%-6.6%, respectively. The inter-batch precision and accuracy of vardenafil were 3.1% -8.4% and -3.7%-4.6%, respectively. In this sample processing method, the extraction recovery rate of vardenafil was obtained at range of 88.2%-104.6%, which met the requirements for the investigation of extraction recovery rate. In this sample processing method, the normalized matrix factor of each quality control concentration of vardenafil was 1.04, 0.85, and 1.04, and the coefficient of variation (%CV) was in the range of 1.7%-10.7%, which met the requirements for the investigation of matrix effects. Variations of short-term stability, long-term stability, and stability of 4 freeze-thaw cycles of vardenafil was within ±15%, and the coefficient of variation were within 5%. Conclusion: The high performance liquid chromatography-tandem mass spectrometry method established in this study is feasible for the measurement of concentration of vardenafil in rat plasma and this method has good specificity and high accuracy, and can be used to detect the concentration of vardenafil in rat plasma.


Assuntos
Espectrometria de Massas em Tandem , Animais , Cromatografia Líquida , Estudos de Viabilidade , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Dicloridrato de Vardenafila
19.
Yakugaku Zasshi ; 140(8): 1035-1040, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32741861

RESUMO

For many of the novel antiepileptics, immunoassays, used for routine therapeutic drug monitoring (TDM), cannot be used. We could monitor eight novel antiepileptics using an LC/MS method since July 2017. The purpose of this study was to evaluate the significant changes associated with the transition from outsourcing to in-hospital monitoring of novel antiepileptics. The number of measurements of novel antiepileptics was significantly increased during the first (p<0.01) and second (p<0.001) years of in-hospital monitoring as compared to that one year prior to in-hospital monitoring which was outsourced. The proportion of measurements of novel antiepileptics to all antiepileptics was 19.7%, 31.1%, and 38.4% during outsourcing, and first, and second years of in-hospital monitoring, respectively. The measurement cost was significantly reduced during the first (p<0.001) and second (p<0.001) years of in-hospital monitoring as compared to that during outsourcing. In addition, the revenue from TDM of antiepileptic drugs was significantly increased during the first (p<0.05) and second (p<0.01) years of in-hospital monitoring as compared with that during outsourcing. In conclusion, the switch from outsourcing to in-hospital monitoring led to an increase in the number of orders, a reduction in the measurement-related expenses of novel antiepileptics, and an increase in the revenue from TDM of antiepileptic drugs, which could promote the proper use of novel antiepileptics through TDM.


Assuntos
Anticonvulsivantes , Monitoramento de Medicamentos/métodos , Monitoramento de Medicamentos/estatística & dados numéricos , Serviços Terceirizados/estatística & dados numéricos , Serviço de Farmácia Hospitalar/estatística & dados numéricos , Cromatografia Líquida , Monitoramento de Medicamentos/economia , Humanos , Renda/estatística & dados numéricos , Espectrometria de Massas , Fatores de Tempo
20.
J Chromatogr A ; 1626: 461283, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797812

RESUMO

Two-dimensional liquid chromatography is increasingly being used to address challenging separations in fields ranging from pharmaceutical analysis to the food industry. A significant impediment to development of more methods is the lack of a complete theoretical foundation upon which sound development decisions can be made. One parameter that is currently not fully understood is the extent of filling of sampling loops in the case where effluent from the first dimension separation is transferred to the second dimension separation through this type of open loop interface. This is a highly important parameter because it is connected to several other variables in a 2D-LC system, including the first dimension flow rate, the sampling (modulation) time, and the loop volume. In this study we have used both numerical simulation methods and experimental measurements to understand the extent to which sampling loops can be filled before a significant fraction of the analyte is lost from the end of the loop. Variables included in the study are the analyte diffusion coefficient (Dmol), loop filling rate (Ffill), loop inner diameter or radius (Rloop) and loop volume (Vloop). For a straight loop capillary we find that analyte breakthrough curves (as measured at the loop outlet) depend only on a single the dimensionless parameter t*=VloopFfill·DmolRloop2 . As a function of this parameter, the fraction of analyte lost from the loop outlet for different extents of loop filling could be calculated, allowing to develop guidelines for the maximum permissible extent of filling before a specified level of analyte loss is reached. Breakthrough measurements using a coiled loop capillary show that less breakthrough is observed compared to the straight capillary at high filling flow rates, presumably due to secondary flows that increase radial dispersion. These measurements enabled the calculation of apparent radial diffusion coefficients for use with coiled capillaries such that the same relation for t* can be used to predict analyte loss due to breakthrough. These results should be very useful to practitioners of 2D-LC, enabling them to make rational decisions about the extent of loop filling on the basis of experimental conditions and analyte type.


Assuntos
Cromatografia Líquida/métodos , Cromatografia Líquida/instrumentação , Difusão , Modelos Teóricos
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