The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry...The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry(GC-MS/MS)based method,various conditions for sterols extraction were assessed and the instrumental operation parameters were optimized with 5α-cholane as an internal standard.Using this method,eight plant sterols,namely lanosterol,campesterol,chenodeoxycholic acid,cholesterol,β-sitosterol,stigmasterol,dihydrotachysterol and ergosterol,were separated in less than 30 min.The linear correlation coefficients were over 0.998 9,the low detection limits were in the range of 0.010 3-0.141 4 μg/g.The recoveries were from 87.30% to 115.60%,with low standard deviations.In conclusion,this method demonstrates good repeatability,accuracy,and high sensitivity,and is best suited for rapid analysis of multiple sterols in tobacco leaves.展开更多
Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues inc...Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues including workplace, court ordered, and substance abuse treatment monitoring. After the presentation of a fully validated 2-dimensional gas chromatography-tandem mass spectrometry method for the detection of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA), the chief metabolite of the main psychoactive compound in marijuana, Δ9-tetrahydrocannabinol (THC), we evaluated the usefulness of fingernail clippings as an alternative specimen type to hair by the analysis of a set of 60 matched pairs of head hair and fingernail clippings. The limit of detection was 10 fg/mg, the limit of quantitation was 20 fg/mg, and the assay was linear from 20 fg/mg to 500 fg/mg. The intra- and inter-assay imprecision and bias studies at 4 different concentrations (50, 100, 500, and 1000 fg/mg) were acceptable where all % Target observations were within 16% of their expected concentrations and all %CV calculations were less than 13.5%. THCA was detectable in more fingernail specimens (53.3%) than hair specimens (46.7%) and the mean concentrations in nails were on average 4.9 times higher than in hair (1813 fg/mg and 364 fg/mg, respectively). The THCA concentrations in hair and nail were strongly associated (r = 0.974, P < 0.01, n = 60) and the association was significant. The study demonstrated that fingernail clippings are a suitable alternative specimen type to hair to monitor for marijuana use and abuse.展开更多
A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in...A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.展开更多
The positive and negative ESI-MS/MS spectra of N-ethoxy（phenyl） phosphoryl amino acids（EPP-AA） were investigated by electrospray ionization（ESI） ion trap mass spectrometry. The fragmentation pathways of [ M ＋ N...The positive and negative ESI-MS/MS spectra of N-ethoxy（phenyl） phosphoryl amino acids（EPP-AA） were investigated by electrospray ionization（ESI） ion trap mass spectrometry. The fragmentation pathways of [ M ＋ Na]^＋ and [ M - H]^- ions are proposed and rationalized. The observation may have some potential applications in the interpretation of the MS/MS spectra of novel N-phosphoryl compounds. The complexity of MS/MS spectra of EPP-AA [ M ＋ Na]^＋ ions is decreased compared with that of N-dialkyloxyphosphoryl amino acid. Therefore, the new phosphonamidate method may be considered one of the superior methods that can be used in sequencing peptides and proteins extensively.展开更多
The fragmentation pathways of two isomers of brassinosteroids,28-homobrassinolide(28-h-BL)and 28-epihomobrassinolide(28-eh-BL),have been investigated by tandem mass spectrometry(MSn,n=1,2,3,4)with the electrospray ion...The fragmentation pathways of two isomers of brassinosteroids,28-homobrassinolide(28-h-BL)and 28-epihomobrassinolide(28-eh-BL),have been investigated by tandem mass spectrometry(MSn,n=1,2,3,4)with the electrospray ionization(ESI) source.The ESI mass spectrometric fragmentation pathways of protonated 28-h-BL and 28-eh-BL were comprehensively elucidated,and the principles revealed in this investigation could potentially be used to identify and distinguish brassinosteroids and their isomers.展开更多
目的基于线性离子阱质谱的多重反应监测-信息依赖采集-增强子离子扫描(multiple reaction monitoring-information dependent acquisition-enhanced product ion scan,MRM-IDA-EPI)二级谱图筛查方法,建立超高效液相色谱-串联质谱法(ultr...目的基于线性离子阱质谱的多重反应监测-信息依赖采集-增强子离子扫描(multiple reaction monitoring-information dependent acquisition-enhanced product ion scan,MRM-IDA-EPI)二级谱图筛查方法,建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)定量检测和定性筛查野生菌中15种蘑菇毒素。方法野生菌样本通过甲酸-甲醇-水-乙腈(1:40:40:19,V:V:V:V)混合溶液超声提取,QuEChERS试剂提取净化,采用UPLC-MS/MS和MRM-IDA-EPI方法对15种蘑菇毒素进行定量分析和定性筛查。结果通过野生菌样本前处理方法和色谱条件优化,对15种蘑菇毒素进行0.04、0.10和0.40 mg/kg三水平加标回收实验,方法准确度为76.6%~109.2%,精密度为0.3%~7.6%;15种蘑菇毒素的线性范围为10~1000μg/L,线性相关系数(r)在0.9980~0.9994之间;其中α-鹅膏毒肽、β-鹅膏毒肽、γ-鹅膏毒肽、光盖伞素和鹅膏蕈氨酸的方法检出限(limits of detection,LODs)和定量限(limits of quantification,LOQs)分别为10μg/kg和30μg/kg,二羟鬼笔毒肽、羧基二羟鬼笔毒肽、羧基三羟鬼笔毒肽、毒蝇碱、蝇蕈醇、甲基裸盖菇素、鹿花菌素、脱磷酸裸盖菇素、奥来毒素和鬼伞菌素的LODs和LOQs分别为20μg/kg和60μg/kg,采用QuEChERS前处理方法对野生菌样本进行处理,样本基质效应系数K值在0.91~1.08之间。结论所建立的野生菌样本前处理方法对15种蘑菇毒素的定量测定无基质干扰,15种蘑菇毒素的UPLC-MS/MS和MRM-IDA-EPI分析方法结果准确、重现性好、灵敏度高,该方法适用于有毒野生菌引起的食源性中毒定量分析和定性筛查。展开更多
运用气相色谱-离子阱质谱（ion trap mass spectrometry，ITMS）建立了大气中8种多溴二苯醚的二级质谱（MS／MS）检测方法。优化后的MS／MS方法对7种三溴至七溴二苯醚（BDE28、-47、-99、-100、-153、-154、-183）和十溴二苯醚（BDE209...运用气相色谱-离子阱质谱（ion trap mass spectrometry，ITMS）建立了大气中8种多溴二苯醚的二级质谱（MS／MS）检测方法。优化后的MS／MS方法对7种三溴至七溴二苯醚（BDE28、-47、-99、-100、-153、-154、-183）和十溴二苯醚（BDE209）的仪器检出限分别为0．04～0．23pg和9．38pg；方法检出限为6．0～27．1pg／m^3和211．6pg／m^3；6点标准曲线相关系数（r）为0．9980～0．9999。方法对8种目标物的加标回收率为79．1％～101．0％，相对标准偏差（RSD）为4．3％～14．3％（n=6）。对6份南京实际大气样品的检测结果表明：离子阱质谱的选择反应监测（selected reaction monitoring，SRM）技术能有效的降低背景干扰。优化后的MS／MS方法对目标化合物有较高的灵敏度，可应用于大气中痕量多溴二苯醚的定量检测。展开更多
文摘The purpose of the study was to establish an analytical method to simultaneously determine multiple sterols in tobacco leaves rapidly and accurately.In this gas chromatography-triple quadruple tandem mass spectrometry(GC-MS/MS)based method,various conditions for sterols extraction were assessed and the instrumental operation parameters were optimized with 5α-cholane as an internal standard.Using this method,eight plant sterols,namely lanosterol,campesterol,chenodeoxycholic acid,cholesterol,β-sitosterol,stigmasterol,dihydrotachysterol and ergosterol,were separated in less than 30 min.The linear correlation coefficients were over 0.998 9,the low detection limits were in the range of 0.010 3-0.141 4 μg/g.The recoveries were from 87.30% to 115.60%,with low standard deviations.In conclusion,this method demonstrates good repeatability,accuracy,and high sensitivity,and is best suited for rapid analysis of multiple sterols in tobacco leaves.
文摘Marijuana use as well as abuse is a significant public health and public safety concern in the United States and using hair to identify marijuana users and abusers has been gaining acceptance in a number of venues including workplace, court ordered, and substance abuse treatment monitoring. After the presentation of a fully validated 2-dimensional gas chromatography-tandem mass spectrometry method for the detection of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THCA), the chief metabolite of the main psychoactive compound in marijuana, Δ9-tetrahydrocannabinol (THC), we evaluated the usefulness of fingernail clippings as an alternative specimen type to hair by the analysis of a set of 60 matched pairs of head hair and fingernail clippings. The limit of detection was 10 fg/mg, the limit of quantitation was 20 fg/mg, and the assay was linear from 20 fg/mg to 500 fg/mg. The intra- and inter-assay imprecision and bias studies at 4 different concentrations (50, 100, 500, and 1000 fg/mg) were acceptable where all % Target observations were within 16% of their expected concentrations and all %CV calculations were less than 13.5%. THCA was detectable in more fingernail specimens (53.3%) than hair specimens (46.7%) and the mean concentrations in nails were on average 4.9 times higher than in hair (1813 fg/mg and 364 fg/mg, respectively). The THCA concentrations in hair and nail were strongly associated (r = 0.974, P < 0.01, n = 60) and the association was significant. The study demonstrated that fingernail clippings are a suitable alternative specimen type to hair to monitor for marijuana use and abuse.
文摘A fast and sensitive method for determination of 8 diuretics (acetazolamide, bendroflumethiazide, bumetanide, chlorthalidone, furosemide, hydrochlorothiazide, metolazone, triamterene) and masking agent (probenecid) in human urine using gas-chromatography with mass spectrometric detection is described. The extraction of the substances as function of the nature of organic solvent, mixing time and pH of aqueous phase was studied. The tandem mass spectrometry was used to increase selectivity of diuretics determination due to elimination of background interferences. Fragmentation reactions were studied for each compound and their collision energies were optimized to obtain the best selectivity. The results of method’s validation demonstrate its suitability in routine analysis for confirmation purposes.
基金Supported by the Education Department of Henan Province(No. 200510459015).
文摘The positive and negative ESI-MS/MS spectra of N-ethoxy（phenyl） phosphoryl amino acids（EPP-AA） were investigated by electrospray ionization（ESI） ion trap mass spectrometry. The fragmentation pathways of [ M ＋ Na]^＋ and [ M - H]^- ions are proposed and rationalized. The observation may have some potential applications in the interpretation of the MS/MS spectra of novel N-phosphoryl compounds. The complexity of MS/MS spectra of EPP-AA [ M ＋ Na]^＋ ions is decreased compared with that of N-dialkyloxyphosphoryl amino acid. Therefore, the new phosphonamidate method may be considered one of the superior methods that can be used in sequencing peptides and proteins extensively.
基金supported by the National Natural Science Foundation of China(90717002 and 90717002)the Fundamental Research Funds for the Central Universitiesthe Project Sponsored by the Scientific Research Fundation for the Returned Overseas Chinese Scholars,Education Ministry of China
文摘The fragmentation pathways of two isomers of brassinosteroids,28-homobrassinolide(28-h-BL)and 28-epihomobrassinolide(28-eh-BL),have been investigated by tandem mass spectrometry(MSn,n=1,2,3,4)with the electrospray ionization(ESI) source.The ESI mass spectrometric fragmentation pathways of protonated 28-h-BL and 28-eh-BL were comprehensively elucidated,and the principles revealed in this investigation could potentially be used to identify and distinguish brassinosteroids and their isomers.
文摘目的基于线性离子阱质谱的多重反应监测-信息依赖采集-增强子离子扫描(multiple reaction monitoring-information dependent acquisition-enhanced product ion scan,MRM-IDA-EPI)二级谱图筛查方法,建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)定量检测和定性筛查野生菌中15种蘑菇毒素。方法野生菌样本通过甲酸-甲醇-水-乙腈(1:40:40:19,V:V:V:V)混合溶液超声提取,QuEChERS试剂提取净化,采用UPLC-MS/MS和MRM-IDA-EPI方法对15种蘑菇毒素进行定量分析和定性筛查。结果通过野生菌样本前处理方法和色谱条件优化,对15种蘑菇毒素进行0.04、0.10和0.40 mg/kg三水平加标回收实验,方法准确度为76.6%~109.2%,精密度为0.3%~7.6%;15种蘑菇毒素的线性范围为10~1000μg/L,线性相关系数(r)在0.9980~0.9994之间;其中α-鹅膏毒肽、β-鹅膏毒肽、γ-鹅膏毒肽、光盖伞素和鹅膏蕈氨酸的方法检出限(limits of detection,LODs)和定量限(limits of quantification,LOQs)分别为10μg/kg和30μg/kg,二羟鬼笔毒肽、羧基二羟鬼笔毒肽、羧基三羟鬼笔毒肽、毒蝇碱、蝇蕈醇、甲基裸盖菇素、鹿花菌素、脱磷酸裸盖菇素、奥来毒素和鬼伞菌素的LODs和LOQs分别为20μg/kg和60μg/kg,采用QuEChERS前处理方法对野生菌样本进行处理,样本基质效应系数K值在0.91~1.08之间。结论所建立的野生菌样本前处理方法对15种蘑菇毒素的定量测定无基质干扰,15种蘑菇毒素的UPLC-MS/MS和MRM-IDA-EPI分析方法结果准确、重现性好、灵敏度高,该方法适用于有毒野生菌引起的食源性中毒定量分析和定性筛查。
