The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
Gas chromatography/inductively coupled plasma mass spectrometry (GC/ICP-MS) coupled with solid phase micro-extraction can provide a simple, extremely selective and sensitive technique for the analysis of volatile sulf...Gas chromatography/inductively coupled plasma mass spectrometry (GC/ICP-MS) coupled with solid phase micro-extraction can provide a simple, extremely selective and sensitive technique for the analysis of volatile sulfur and selenium compounds in the headspace of growing plants. In this work, the technique was used to evaluate the volatilization of selenium in wild-type and genetically-modified Brassica juncea seedlings. By converting toxic inorganic selenium in the soil to less toxic, volatile organic selenium, B. juncea might be useful in bioremediation of selenium contaminated soil.展开更多
The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples...The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.展开更多
In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purificatio...In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.展开更多
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
Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In t...Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.展开更多
Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, s...Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, some compounds do not show enough sensitivity in LC/MS and soft ionization methods commonly used in LC/MS, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), sometimes do not give satisfactory structural information This report presents an overview of the derivatization methods in the LC/MS analysis of neurosteroids or neuroactive neurosteroids, which are synthesized and accumulated in the nervous system The derivatization of pregnenolone 3 sulfate, one of these steroids, with 4 ( N,N dimethylaminosulfonyl) 7 hydrazino 2,1,3 benzoxadiazole gave a satisfactory sensitivity during the quantitative analysis using LC/ESI MS The obtained results are much lower than those previously obtained using gas chromatography/mass spectrometry or radioimmunoassay On the other hand, the derivatization to acetate was useful for the treatment of labile catechol estrogens in rat brains and gave enough structural information in LC/APCI MS, which confirmed the existence of catechol estrogens in mammalian展开更多
Chinese herbal compound is playing an important role on curing human diseases.And it has been a trend that Chinese herbal compound is being used all over the world in 21 century.However,our Chinese herbal compound is ...Chinese herbal compound is playing an important role on curing human diseases.And it has been a trend that Chinese herbal compound is being used all over the world in 21 century.However,our Chinese herbal compound is facing serious challenge for the lack of canonical system of quality criterion for Chinese herbal compound so it has been a urgent problem to set up the quality control standards and reveal therapeutic basis of Chinese herbal compound.In order to give full play to the advantages of Chinese herbal compound,modern scientific and technological is used to research of Chinese herbal compound,especially the high performance liquid chromatography tandem mass spectrometry(HPLC-MS),because it is high sensitive,rapid,and obtain more information.It is very necessary that HPLC-MS is uesed to elucidate the effective components of basic substances of Chinese Herbal Compound,and endow traditional Chinese medicine with modern scientific connotation.展开更多
A rapid method was presented for the determination of 19 polyphenols in tea by ultra-high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).Tea samples were extr...A rapid method was presented for the determination of 19 polyphenols in tea by ultra-high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).Tea samples were extracted by 50%(V/V)ethanol,then separated by Waters Acquity BEH C18 column using a binary solvent system composed of acetonitrile and water(0.1%formic acid)by gradient elution.The analytes were determined by Q-TOF MS in TOF MS and information dependent acquisition(IDA)-MS/MS mode.The results showed that mass accuracy error of the 19 polyphenols were lower than 5.0×10^(-6),good linear relationship was got in range of 0.2–500μg/L and correlation coefficient was higher than 0.9990.The LOD was in the range of 0.002–0.100 mg/kg and the LOQ was in the range of 0.004–0.200 mg/kg.Recovery of the method was in range of 78.4%–109.2%with spike levels of 0.004–2.000 mg/kg,relative standard deviations were lower than 10%.The method was simple,rapid and accurate.It could be used for the rapid screening and quantitative analysis of 19 polyphenols in tea.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
建立了液相色谱-串联质谱(LC-MS/MS)手性拆分和测定水产品中奥沙西泮和替马西泮对映体残留量的分析方法。样品经乙腈提取2次,40℃条件下氮气浓缩至近干,残渣加入2 mL 50%乙腈-水溶液溶解,采用分散固相萃取净化,LC-MS/MS测定。使用Enanti...建立了液相色谱-串联质谱(LC-MS/MS)手性拆分和测定水产品中奥沙西泮和替马西泮对映体残留量的分析方法。样品经乙腈提取2次,40℃条件下氮气浓缩至近干,残渣加入2 mL 50%乙腈-水溶液溶解,采用分散固相萃取净化,LC-MS/MS测定。使用EnantioPAK■Y1-R(5μm,150 mm×4.6 mm)手性色谱柱,乙腈和0.1%甲酸-5 mmol/L乙酸铵溶液作为流动相,采用等度洗脱方式实现奥沙西泮和替马西泮手性对映体的拆分。目标对映体采用电喷雾正离子(ESI^(+))模式电离,多反应监测(MRM)模式下,内标法测定。目标对映体在0.5~50μg/L质量浓度范围内线性关系良好,相关系数(r^(2))均不低于0.9990。水产品中对映体的检出限和定量下限分别为0.2μg/kg和0.5μg/kg。在5种空白基质中添加低、中、高浓度水平的目标对映体,样品平均加标回收率为82.6%~107%,相对标准偏差(RSD,n=6)为1.6%~9.2%。该方法灵敏可靠、适用性强,可用于不同水产品中奥沙西泮和替马西泮对映体的分析。展开更多
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
文摘Gas chromatography/inductively coupled plasma mass spectrometry (GC/ICP-MS) coupled with solid phase micro-extraction can provide a simple, extremely selective and sensitive technique for the analysis of volatile sulfur and selenium compounds in the headspace of growing plants. In this work, the technique was used to evaluate the volatilization of selenium in wild-type and genetically-modified Brassica juncea seedlings. By converting toxic inorganic selenium in the soil to less toxic, volatile organic selenium, B. juncea might be useful in bioremediation of selenium contaminated soil.
基金This work was supported by“National Key Research and Development Program of China”(Project No.2018YFC1603400)Science and Technology Program of Hebei Province(Project No.19225503D).
文摘The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.
基金National Key Research and Development Program of China(Project No.2018YFC1603400)Science and Technology Program of Hebei Province(Project No.19225503D)Technical Support Project of State Administration for Market Regulation(Project No.2019YJ009).
文摘In this experiment,a liquid chromatography tandem mass spectrometry method was built to determine 15 pesticide residues in Chinese cabbage and cucumber samples based on online turbulent flow chromatography purification.After modified quick,easy,cheap,effective,rugged,and safe(QuEChERS)extraction,extracts were directly injected to the TLX(TurboFlow Liquid Xcalibur)system and brought to TurboFlow™columns for on-line purification and then transferred to analytical column for further separation and analysis.TurboFlow™columns types,transfer flow rate,and transfer time were optimized.Limits of detection and limits of quantification of the method obtained for 15 pesticide residues were ranged between 0.2–1.0μg/kg and 0.5–2.0μg/kg in Chinese cabbage and cucumber samples.Recoveries of pesticide residues were in range of 75.3%–103.7%.Matrix effects for 15 pesticides were in range of 5.6%–106.6%.The developed method has been successfully used for the determination of 15 pesticide residues in real samples.
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.
基金the supports of the National Key Research and Development of BioBased Rubber(2017YFB0306900&2017YFB0306901)the National Natural Science Foundation of China(51673012)+1 种基金the Fundamental Research Funds for the Central Universities(PYBZ1828)the Beijing Technology and Business Universtiy Youth Scholoars Funds(PXM2019014213000007)。
文摘Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.
文摘Liquid chromatography/mass spectrometry (LC/MS) is now considered to be the most promising analytical method for the determination of biological substances, especially nonvolatile or highly polar substances However, some compounds do not show enough sensitivity in LC/MS and soft ionization methods commonly used in LC/MS, such as electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), sometimes do not give satisfactory structural information This report presents an overview of the derivatization methods in the LC/MS analysis of neurosteroids or neuroactive neurosteroids, which are synthesized and accumulated in the nervous system The derivatization of pregnenolone 3 sulfate, one of these steroids, with 4 ( N,N dimethylaminosulfonyl) 7 hydrazino 2,1,3 benzoxadiazole gave a satisfactory sensitivity during the quantitative analysis using LC/ESI MS The obtained results are much lower than those previously obtained using gas chromatography/mass spectrometry or radioimmunoassay On the other hand, the derivatization to acetate was useful for the treatment of labile catechol estrogens in rat brains and gave enough structural information in LC/APCI MS, which confirmed the existence of catechol estrogens in mammalian
文摘Chinese herbal compound is playing an important role on curing human diseases.And it has been a trend that Chinese herbal compound is being used all over the world in 21 century.However,our Chinese herbal compound is facing serious challenge for the lack of canonical system of quality criterion for Chinese herbal compound so it has been a urgent problem to set up the quality control standards and reveal therapeutic basis of Chinese herbal compound.In order to give full play to the advantages of Chinese herbal compound,modern scientific and technological is used to research of Chinese herbal compound,especially the high performance liquid chromatography tandem mass spectrometry(HPLC-MS),because it is high sensitive,rapid,and obtain more information.It is very necessary that HPLC-MS is uesed to elucidate the effective components of basic substances of Chinese Herbal Compound,and endow traditional Chinese medicine with modern scientific connotation.
基金supported by National Key Research and Development Program of China(2018YFC1603400)。
文摘A rapid method was presented for the determination of 19 polyphenols in tea by ultra-high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry(UPLC-Q-TOF MS).Tea samples were extracted by 50%(V/V)ethanol,then separated by Waters Acquity BEH C18 column using a binary solvent system composed of acetonitrile and water(0.1%formic acid)by gradient elution.The analytes were determined by Q-TOF MS in TOF MS and information dependent acquisition(IDA)-MS/MS mode.The results showed that mass accuracy error of the 19 polyphenols were lower than 5.0×10^(-6),good linear relationship was got in range of 0.2–500μg/L and correlation coefficient was higher than 0.9990.The LOD was in the range of 0.002–0.100 mg/kg and the LOQ was in the range of 0.004–0.200 mg/kg.Recovery of the method was in range of 78.4%–109.2%with spike levels of 0.004–2.000 mg/kg,relative standard deviations were lower than 10%.The method was simple,rapid and accurate.It could be used for the rapid screening and quantitative analysis of 19 polyphenols in tea.
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.
