The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tande...The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.展开更多
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
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
To establish HPLC electrospray ionization mass spectrometry (HPLC-ESI MS) method for determination of osthole in food additive.The samples were dipped in methanol overnight and extracted with it by ultrasonic instrume...To establish HPLC electrospray ionization mass spectrometry (HPLC-ESI MS) method for determination of osthole in food additive.The samples were dipped in methanol overnight and extracted with it by ultrasonic instrument,then the supernatant was send to sampler for detection.Sample was chromatographed using 0.4%HAc solution-MeOH (35:65,by volume) mobile phase on an Xterra MS C18 column.Analyte determination was performed by ESI MS/MS in the multiple reaction monitoring(MRM)mode.The established method of LC-MS/MS determining the concentration of osthole in food additive has the characteristic of strong specificity,high sensitivity and good reproducibility.The linear range of papaverine was 0.001-10 μg/mL,method recovery was 97.42%,RSD was 8.37%,the limit of detection was 1 ng/mL and the limit of quantitation was 0.001 μg/mL.展开更多
文摘The measurement of urine catecholamine and metanephrine concentrations is important for biochemical screening and diagnosis of pheochromocytoma.The goal of this work was to develop a simple liquid chromatography-tandem mass spectrometry(LC-MS/MS)method for determining catecholamines and metanephrines in urine to replace an existing liquid chromatographic method using electrochemical detection.Urine samples were prepared using Oasis weak-cation-exchange cartridges.The eluate was analyzed on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column in 3 min.Adrenaline,noradrenaline,dopamine,metanephrine,normetanephrine,and their deuterated internal standards were monitored in positive electrospray ionization mode by multiple reaction monitoring(MRM).No evidence of ion suppression was observed.The assay was linear up to 5μmol/L for adrenaline,5μmol/L for noradrenaline,6.1μmol/L for dopamine,5.6μmol/L for metanephrine,and 34.6μmol/L for normetanephrine,with lower limits of quantification of 5,5,12,6 and 7nmol/L,respectively.The intra-day and inter-day precisions for all analytes ranged from 0.59%to 4.64%and1.98%to 4.80%,respectively.External quality assurance samples were assayed and showed excellent agreement with the target values.This simple method provides an improved assay for determining urine catecholamines and metanephrines.
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.
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。
文摘To establish HPLC electrospray ionization mass spectrometry (HPLC-ESI MS) method for determination of osthole in food additive.The samples were dipped in methanol overnight and extracted with it by ultrasonic instrument,then the supernatant was send to sampler for detection.Sample was chromatographed using 0.4%HAc solution-MeOH (35:65,by volume) mobile phase on an Xterra MS C18 column.Analyte determination was performed by ESI MS/MS in the multiple reaction monitoring(MRM)mode.The established method of LC-MS/MS determining the concentration of osthole in food additive has the characteristic of strong specificity,high sensitivity and good reproducibility.The linear range of papaverine was 0.001-10 μg/mL,method recovery was 97.42%,RSD was 8.37%,the limit of detection was 1 ng/mL and the limit of quantitation was 0.001 μg/mL.
