Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC...Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)in positive electrospray ionization mode.Extraction and clean-up were achieved using a ChemElut cartridge with tert-butyl methyl ether,without a derivatization step.Separation was achieved on an Acquity UPLC SS T3 column.The mobile phase was acetonitrile and water containing 0.2%(v/v)formic acid.The mass spectrometer was operated in multiple reaction monitoring mode.Urine samples were spiked with TS solution at levels corresponding to 5,10,15,and 20μg/L.The accuracy(internal standard corrected)ranged from 92%to 107%,with a repeatability precision(relative standard deviation,RSD)less than 15%for all five analytes.The RSDs within-laboratory reproducibility was less than 26%.The decision limits(CCα)and detection capabilities(CCβ)were obtained from a calibration curve and were in the ranges of 3.1-6.1μg/L and 4.0-7.4μg/L,respectively.The CCαand CCβvalues were below the recommended concentration,which was set at 10μg/L.The results show that the described method is suitable for the direct detection of TSs in bovine urine.This method can also be used to determine TSs in porcine urine.展开更多
Humic acids can promote the germination of many vegetable seeds,but the key active components remain unclear.This study utilized nutrient content,cross polarization magic angle spin ^(13)C solid magnetic resonance(CPM...Humic acids can promote the germination of many vegetable seeds,but the key active components remain unclear.This study utilized nutrient content,cross polarization magic angle spin ^(13)C solid magnetic resonance(CPMAS-^(13)C-NMR)and ultra-high performance liquid chromatography-mass spectrometry(UHPLC-MS)to characterize the chemical components of humic acids.Tomato seed germination index(GI)was determined with the goal of screening the key active components of humic acids.Humic acids had a significantly higher nutrient content,except for the total nitrogen(TN)and the total phosphorus(TP)contents.Humic acids had a higher content of O-CH_(3)/NCH,aromatic C-O and carbonyl C compared to weathered coal,with significantly lower anomeric C,aromatic C and O-alkyl C/alkyl C.There were 611 different compounds identified among the test materials using UHPLC-MS.Humic acids also had a significantly higher GI(158.0%and 153.1%)than weathered coal(85.5%).The organic matter(OM),TP and available potassium(AK)contents in humic acids were significantly positively correlated with GI,and available phosphorus(AP)was significantly negatively correlated.Among the carbon components,O-CH3/NCH,aromatic C-O and O-alkyl C/alkyl C were significantly positively correlated with GI,while anomeric C was significantly negatively correlated.Furthermore,among the top 10 positive and five negative correlation compounds,lipids and lipid-like molecules[armexifolin,boviquinone 4,3-methyladipic acid,lxocarpalactone A,monic acid,DG(20:1(11Z)/18:4(6Z,9Z,12Z,15Z)/0:0),and brassinolide]and organic acids and derivatives(N-acetylglutamic acid,8-hydroxy-5,6-octadienoic acid,acetyl-L-tyrosine,and hydroxyprolyl-methionine)in humic acids might be crucial active components for improving tomato seed germination.The results provided direct evidence for the identification of bioactive molecules of humic acids,and a scientific basis for the precise utilization of bioactive molecular components of humic acids in sustainable agricultural development.展开更多
A simple and sensitive method was developed for the simultaneous determination of four macrolides in pork using high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).Homogenized sample was extrac...A simple and sensitive method was developed for the simultaneous determination of four macrolides in pork using high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).Homogenized sample was extracted with NaH2PO4 buffer and acetonitrile solution,and defatted with n-hexane.Further cleanup was performed on a Sep-Pakt C18 solid-phase extraction cartridge.The compounds were determined by LC-MS/MS operated in positive electrospray ionization mode.The limits of detection(LODs) were 0.5 μg/kg.The average recoveries at three spiked concentration levels of 1.0,5.0,10.0 μg/kg were in the range of 70%-110%,with the intra-day RSD of less than 12.9% and inter-day RSD of less than 13.4%.展开更多
建立了分析测定水环境中十氯酮的液相色谱-串联质谱法。水样经液液萃取、净化后，采用 Eclipse plus C18柱（100 mm×2.1 mm，3.5μm）分离，乙腈和水为流动相进行梯度洗脱，在电喷雾负离子多反应监测模式下进行检测，同位素内标法...建立了分析测定水环境中十氯酮的液相色谱-串联质谱法。水样经液液萃取、净化后，采用 Eclipse plus C18柱（100 mm×2.1 mm，3.5μm）分离，乙腈和水为流动相进行梯度洗脱，在电喷雾负离子多反应监测模式下进行检测，同位素内标法定量。结果表明：采用液相色谱-质谱联用技术，证实了十氯酮在甲醇中以半缩醛的形式存在，而在丙酮/乙腈中以偕二醇的形式存在。由于十氯酮极性较强，在净化时难以洗脱，并且不耐酸，所以不能与其他有机氯农药一起分析。十氯酮在5～100μg / L 范围有良好的线性关系，相关系数 r2=0.999，检出限及定量限分别为0.70 ng / L 和2.8 ng / L；在5、40和100 ng / L 3个浓度添加水平的平均回收率为95.1％～98.9％，相对标准偏差为3.85％～4.72％。本方法具有良好的灵敏度、回收率和重现性，适用于水环境中十氯酮的测定。展开更多
Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of iso...Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.展开更多
文摘Five thyreostats(TSs),namely tapazole,thiouracil,methylthiouracil,propylthiouracil,and phenylthiouracil,were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry(UHPLC-MS/MS)in positive electrospray ionization mode.Extraction and clean-up were achieved using a ChemElut cartridge with tert-butyl methyl ether,without a derivatization step.Separation was achieved on an Acquity UPLC SS T3 column.The mobile phase was acetonitrile and water containing 0.2%(v/v)formic acid.The mass spectrometer was operated in multiple reaction monitoring mode.Urine samples were spiked with TS solution at levels corresponding to 5,10,15,and 20μg/L.The accuracy(internal standard corrected)ranged from 92%to 107%,with a repeatability precision(relative standard deviation,RSD)less than 15%for all five analytes.The RSDs within-laboratory reproducibility was less than 26%.The decision limits(CCα)and detection capabilities(CCβ)were obtained from a calibration curve and were in the ranges of 3.1-6.1μg/L and 4.0-7.4μg/L,respectively.The CCαand CCβvalues were below the recommended concentration,which was set at 10μg/L.The results show that the described method is suitable for the direct detection of TSs in bovine urine.This method can also be used to determine TSs in porcine urine.
基金Supported by the National Natural Science Foundation of China(42207371)the Technological Project of Jiangsu Vocational College of Agriculture and Forestry(2021kj17)+1 种基金Yafu Technology Innovation and Service Major Project of Jiangsu Vocational College of Agriculture and Forestry(2024kj01)Key Research Projects of Jiangsu Vocational College of Agriculture and Forestry(2023kj14)。
文摘Humic acids can promote the germination of many vegetable seeds,but the key active components remain unclear.This study utilized nutrient content,cross polarization magic angle spin ^(13)C solid magnetic resonance(CPMAS-^(13)C-NMR)and ultra-high performance liquid chromatography-mass spectrometry(UHPLC-MS)to characterize the chemical components of humic acids.Tomato seed germination index(GI)was determined with the goal of screening the key active components of humic acids.Humic acids had a significantly higher nutrient content,except for the total nitrogen(TN)and the total phosphorus(TP)contents.Humic acids had a higher content of O-CH_(3)/NCH,aromatic C-O and carbonyl C compared to weathered coal,with significantly lower anomeric C,aromatic C and O-alkyl C/alkyl C.There were 611 different compounds identified among the test materials using UHPLC-MS.Humic acids also had a significantly higher GI(158.0%and 153.1%)than weathered coal(85.5%).The organic matter(OM),TP and available potassium(AK)contents in humic acids were significantly positively correlated with GI,and available phosphorus(AP)was significantly negatively correlated.Among the carbon components,O-CH3/NCH,aromatic C-O and O-alkyl C/alkyl C were significantly positively correlated with GI,while anomeric C was significantly negatively correlated.Furthermore,among the top 10 positive and five negative correlation compounds,lipids and lipid-like molecules[armexifolin,boviquinone 4,3-methyladipic acid,lxocarpalactone A,monic acid,DG(20:1(11Z)/18:4(6Z,9Z,12Z,15Z)/0:0),and brassinolide]and organic acids and derivatives(N-acetylglutamic acid,8-hydroxy-5,6-octadienoic acid,acetyl-L-tyrosine,and hydroxyprolyl-methionine)in humic acids might be crucial active components for improving tomato seed germination.The results provided direct evidence for the identification of bioactive molecules of humic acids,and a scientific basis for the precise utilization of bioactive molecular components of humic acids in sustainable agricultural development.
文摘A simple and sensitive method was developed for the simultaneous determination of four macrolides in pork using high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).Homogenized sample was extracted with NaH2PO4 buffer and acetonitrile solution,and defatted with n-hexane.Further cleanup was performed on a Sep-Pakt C18 solid-phase extraction cartridge.The compounds were determined by LC-MS/MS operated in positive electrospray ionization mode.The limits of detection(LODs) were 0.5 μg/kg.The average recoveries at three spiked concentration levels of 1.0,5.0,10.0 μg/kg were in the range of 70%-110%,with the intra-day RSD of less than 12.9% and inter-day RSD of less than 13.4%.
文摘建立了分析测定水环境中十氯酮的液相色谱-串联质谱法。水样经液液萃取、净化后，采用 Eclipse plus C18柱（100 mm×2.1 mm，3.5μm）分离，乙腈和水为流动相进行梯度洗脱，在电喷雾负离子多反应监测模式下进行检测，同位素内标法定量。结果表明：采用液相色谱-质谱联用技术，证实了十氯酮在甲醇中以半缩醛的形式存在，而在丙酮/乙腈中以偕二醇的形式存在。由于十氯酮极性较强，在净化时难以洗脱，并且不耐酸，所以不能与其他有机氯农药一起分析。十氯酮在5～100μg / L 范围有良好的线性关系，相关系数 r2=0.999，检出限及定量限分别为0.70 ng / L 和2.8 ng / L；在5、40和100 ng / L 3个浓度添加水平的平均回收率为95.1％～98.9％，相对标准偏差为3.85％～4.72％。本方法具有良好的灵敏度、回收率和重现性，适用于水环境中十氯酮的测定。
基金Supported by the Youth Fund Project from Beijing Academy of Agricultural and Forestry Sciences(QNJJ202001)。
文摘Douchi is a kind of traditional Chinese fermented soybean food.Ultra-high performance liquid chromatography quadrupole-time of flight mass spectrometry(UPLC-QTOF-MS)was applied to separate and identify 12 kinds of isoflavones in Douchi within 16 min.The chromatographic separation was carried out on an ACQUITY UPLC HSS T3 column with a gradient elution program where water containing 0.1%formic acid and acetonitrile containing 0.1%formic acid were used as mobile phases.Detection by using electrospray ionization of positive ion mode was applied in the mass spectrometry.Isoflavones were identified by determining the accurate mass and referring to references in this study.
