As a new technology of analyzing crude oils,comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GCTOFMS) has received much research attention.Here we present a case s...As a new technology of analyzing crude oils,comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GCTOFMS) has received much research attention.Here we present a case study in the Junggar Basin of NW China.Results show that the hydrocarbons,including saturates and aromatics,were all well-separated without large coelution,which cannot be realized by conventional one-dimensional GC-MS.The GC×GC technique is especially effective for analyzing aromatics and low-to-middlemolecular-weight hydrocarbons,such as diamondoids.The geochemical characteristics of crude oils in the study area were investigated through geochemical parameters extracted by GC×GC-TOFMS,improving upon the understanding obtained by GC-MS.Thus,the work here represents a new successful application of GC×GCTOFMS,showing its broad usefulness in petroleum geochemistry.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
Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively...Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively inert, causing no irritation and allergies. Poly(ethylene oxide)(PEO) hydrogels were prepared using pentaerythritol tetra-acrylate(PETRA) as UV crosslinking agent. A simple, accurate, and robust quantitation method was developed based on gas chromatographic techniques(GC), which is suitable for routine analysis of residual PETRA monomers in these hydrogels. Unreacted PETRA was initially identified using gas chromatography–mass spectrometry(GC–MS). The quantitation of analyte was performed and validated using gas chromatography equipped with a flame ionization detector(GC–FID). A linear relationship was obtained over the range of 0.0002%–0.0450%(m/m) with a correlation coefficient(r2)greater than 0.99. The recovery( 4 90%), intra-day precision(%RSD o 0.67), inter-day precision(%RSD o2.5%), and robustness(%RSD o1.62%) of the method were within the acceptable values. The limit of detection(LOD) and limit of quantitation(LOQ) were 0.0001%(m/m) and 0.0002%(m/m), respectively.This assay provides a simple and quick way of screening for residual acrylate monomer in hydrogels.展开更多
建立了双水相萃取结合气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定酱香型白酒中挥发性酚类化合物的方法,该方法简单、高效,可快速定量分析酱香型白酒中的7种酚类化合...建立了双水相萃取结合气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定酱香型白酒中挥发性酚类化合物的方法,该方法简单、高效,可快速定量分析酱香型白酒中的7种酚类化合物。对市售不同品牌系列酱香型白酒及GT提供的一至七轮次酱香型白酒基酒中酚类化合物的含量分布规律进行探索,结果表明,7种酚类化合物的分离效果良好,线性范围为0.0200~10.0000μg/mL,相关系数(R2)均大于0.999,精密度在1.17%~7.64%,回收率为90.74%~120.16%,检出限为0.0011~0.0041μg/mL,定量限为0.0037~0.0137μg/mL。系列酱香型白酒中除JT4、JT5、LT4、LT5未全部检出外,其余样品均检测出7种酚类化合物,酚类化合物的浓度范围是0.0000~0.9268μg/mL。其中4-乙基苯酚(4-Ethylphenol,4-EP)和4-乙基愈创木酚(4-Ethylguaiacol,4-EG)总量的浓度范围是0.0072~0.1275μg/mL,含量最高的是MT3。所选酱香型白酒中4-EP和4-EG总量均小于400μg/L,不会对酒体造成影响。在系列酒中,酚类化合物平均含量GT系列最高(0.6354μg/mL),其次是MT系列(0.5561μg/mL),最低的是LT系列(0.2175μg/mL)。在轮次基酒中,一轮次基酒的酚类化合物总量最高,为0.0373μg/mL,最低的是三轮次,为0.2101μg/mL。同时一轮次中的愈创木酚(Guaiacol,Gua)、4-甲基愈创木酚(4-Methylguaiacol,4-MG)、苯酚(Phenol,Phe)、4-EG、4-乙烯基愈创木酚(4-Vinylguaiacol,4-VG)等物质的含量也显著高于其他轮次基酒,四轮、五轮、六轮次酚类物质的总质量浓度较为接近。展开更多
建立了一步式QuEChERS自动提取和净化技术结合气相色谱-串联质谱同时测定风干牦牛肉中15种N-亚硝胺的分析方法。样品水化后,经乙腈提取,加入4.0 g MgSO_(4)和1.0 g NaCl除水,经十八烷基硅烷(C_(18))和N-丙基乙二胺(PSA)填料净化,采用DB-...建立了一步式QuEChERS自动提取和净化技术结合气相色谱-串联质谱同时测定风干牦牛肉中15种N-亚硝胺的分析方法。样品水化后,经乙腈提取,加入4.0 g MgSO_(4)和1.0 g NaCl除水,经十八烷基硅烷(C_(18))和N-丙基乙二胺(PSA)填料净化,采用DB-HeavyWAX色谱柱(30 m×0.25 mm×0.25μm)分离15种N-亚硝胺,在多重反应监测(MRM)模式下进行测定,外标法定量。结果表明,15种N-亚硝胺分离性能良好,在0.1~200μg/L范围内线性关系良好,相关系数(r^(2))≥0.999 0;检出限(LOD)为0.05~0.20μg/kg,定量限(LOQ)为0.10~0.50μg/kg;在1倍、2倍和10倍LOQ 3个添加水平下的平均回收率分别为79.4%~102.1%、80.6%~109.5%、83.0%~110.6%,相对标准偏差(RSD)为0.8%~16.0%。应用建立的方法检测2种不同加工工艺的市售样品,其中7种N-亚硝胺类化合物(N-亚硝基二甲胺、N-亚硝基二异丁胺、N-亚硝基二正丁胺、N-亚硝基甲基苯胺、N-亚硝基乙基苯胺、N-亚硝基吡咯烷、N-亚硝基二苯胺)均有不同程度检出,平均含量为0.08~20.18μg/kg,且熟制风干牦牛肉中N-亚硝胺的检出率和平均含量均高于传统生制风干牦牛肉。该方法实现了前处理的自动化,相较于其他传统方法,操作简单,实验效率高,人为影响因素小,检测灵敏度高,适用于风干牦牛肉中15种N-亚硝胺的快速测定,为研究肉制品中N-亚硝胺的测定提供了方法支持。展开更多
为了揭示青花菜花球表面蜡粉代谢物的成分差异,以青花菜蜡粉缺失突变体和野生型为试材,基于气相色谱-质谱(gas chromatography tandem time-of-flight mass spectrometry,GC-TOF-MS)联用技术的非靶向代谢组学,对青花菜蜡粉缺失突变体和...为了揭示青花菜花球表面蜡粉代谢物的成分差异,以青花菜蜡粉缺失突变体和野生型为试材,基于气相色谱-质谱(gas chromatography tandem time-of-flight mass spectrometry,GC-TOF-MS)联用技术的非靶向代谢组学,对青花菜蜡粉缺失突变体和野生型的花球主要代谢通路及其产物进行深入分析,并采用单变量和多元变量统计分析及数据库注释筛选差异显著的代谢物。结果表明,青花菜花蕾蜡粉中共检测出显著差异代谢物24种,包括14种氨基酸类、4种有机酸类、1种脂肪酸类、1种胺类、1种糖类和3种其他类次生代谢物;其中,下调的有18种,包括了13种氨基酸类。综合富集分析和拓扑分析获得11条重要性凸显的代谢通路,其中差异最显著的代谢通路是氨基酸的生物合成,其次是次生代谢物的生物合成;而重要性最大的是色氨酸代谢。推测青花菜蜡粉缺失可以通过调节色氨酸代谢、次生代谢物生物合成以及氨基酸生物合成等途径,调节青花菜花蕾中氨基酸类和有机酸类等次生代谢产物的物质含量,进而调控花球的生长、营养品质以及耐寒性。展开更多
基金funded by the Major State Basic Research Development Program of China(973 project,Grant No.2012CB214803)National Science and Technology Major Project of China(Grant No. 2016ZX05003-005)National Natural Science Foundation of China(Grant Nos.41322017 and 41472100)
文摘As a new technology of analyzing crude oils,comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry(GC×GCTOFMS) has received much research attention.Here we present a case study in the Junggar Basin of NW China.Results show that the hydrocarbons,including saturates and aromatics,were all well-separated without large coelution,which cannot be realized by conventional one-dimensional GC-MS.The GC×GC technique is especially effective for analyzing aromatics and low-to-middlemolecular-weight hydrocarbons,such as diamondoids.The geochemical characteristics of crude oils in the study area were investigated through geochemical parameters extracted by GC×GC-TOFMS,improving upon the understanding obtained by GC-MS.Thus,the work here represents a new successful application of GC×GCTOFMS,showing its broad usefulness in petroleum geochemistry.
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.
文摘Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively inert, causing no irritation and allergies. Poly(ethylene oxide)(PEO) hydrogels were prepared using pentaerythritol tetra-acrylate(PETRA) as UV crosslinking agent. A simple, accurate, and robust quantitation method was developed based on gas chromatographic techniques(GC), which is suitable for routine analysis of residual PETRA monomers in these hydrogels. Unreacted PETRA was initially identified using gas chromatography–mass spectrometry(GC–MS). The quantitation of analyte was performed and validated using gas chromatography equipped with a flame ionization detector(GC–FID). A linear relationship was obtained over the range of 0.0002%–0.0450%(m/m) with a correlation coefficient(r2)greater than 0.99. The recovery( 4 90%), intra-day precision(%RSD o 0.67), inter-day precision(%RSD o2.5%), and robustness(%RSD o1.62%) of the method were within the acceptable values. The limit of detection(LOD) and limit of quantitation(LOQ) were 0.0001%(m/m) and 0.0002%(m/m), respectively.This assay provides a simple and quick way of screening for residual acrylate monomer in hydrogels.
文摘建立了双水相萃取结合气相色谱-三重四极杆串联质谱法(gas chromatography-triple quadrupole tandem mass spectrometry,GC-MS/MS)测定酱香型白酒中挥发性酚类化合物的方法,该方法简单、高效,可快速定量分析酱香型白酒中的7种酚类化合物。对市售不同品牌系列酱香型白酒及GT提供的一至七轮次酱香型白酒基酒中酚类化合物的含量分布规律进行探索,结果表明,7种酚类化合物的分离效果良好,线性范围为0.0200~10.0000μg/mL,相关系数(R2)均大于0.999,精密度在1.17%~7.64%,回收率为90.74%~120.16%,检出限为0.0011~0.0041μg/mL,定量限为0.0037~0.0137μg/mL。系列酱香型白酒中除JT4、JT5、LT4、LT5未全部检出外,其余样品均检测出7种酚类化合物,酚类化合物的浓度范围是0.0000~0.9268μg/mL。其中4-乙基苯酚(4-Ethylphenol,4-EP)和4-乙基愈创木酚(4-Ethylguaiacol,4-EG)总量的浓度范围是0.0072~0.1275μg/mL,含量最高的是MT3。所选酱香型白酒中4-EP和4-EG总量均小于400μg/L,不会对酒体造成影响。在系列酒中,酚类化合物平均含量GT系列最高(0.6354μg/mL),其次是MT系列(0.5561μg/mL),最低的是LT系列(0.2175μg/mL)。在轮次基酒中,一轮次基酒的酚类化合物总量最高,为0.0373μg/mL,最低的是三轮次,为0.2101μg/mL。同时一轮次中的愈创木酚(Guaiacol,Gua)、4-甲基愈创木酚(4-Methylguaiacol,4-MG)、苯酚(Phenol,Phe)、4-EG、4-乙烯基愈创木酚(4-Vinylguaiacol,4-VG)等物质的含量也显著高于其他轮次基酒,四轮、五轮、六轮次酚类物质的总质量浓度较为接近。
文摘建立了一步式QuEChERS自动提取和净化技术结合气相色谱-串联质谱同时测定风干牦牛肉中15种N-亚硝胺的分析方法。样品水化后,经乙腈提取,加入4.0 g MgSO_(4)和1.0 g NaCl除水,经十八烷基硅烷(C_(18))和N-丙基乙二胺(PSA)填料净化,采用DB-HeavyWAX色谱柱(30 m×0.25 mm×0.25μm)分离15种N-亚硝胺,在多重反应监测(MRM)模式下进行测定,外标法定量。结果表明,15种N-亚硝胺分离性能良好,在0.1~200μg/L范围内线性关系良好,相关系数(r^(2))≥0.999 0;检出限(LOD)为0.05~0.20μg/kg,定量限(LOQ)为0.10~0.50μg/kg;在1倍、2倍和10倍LOQ 3个添加水平下的平均回收率分别为79.4%~102.1%、80.6%~109.5%、83.0%~110.6%,相对标准偏差(RSD)为0.8%~16.0%。应用建立的方法检测2种不同加工工艺的市售样品,其中7种N-亚硝胺类化合物(N-亚硝基二甲胺、N-亚硝基二异丁胺、N-亚硝基二正丁胺、N-亚硝基甲基苯胺、N-亚硝基乙基苯胺、N-亚硝基吡咯烷、N-亚硝基二苯胺)均有不同程度检出,平均含量为0.08~20.18μg/kg,且熟制风干牦牛肉中N-亚硝胺的检出率和平均含量均高于传统生制风干牦牛肉。该方法实现了前处理的自动化,相较于其他传统方法,操作简单,实验效率高,人为影响因素小,检测灵敏度高,适用于风干牦牛肉中15种N-亚硝胺的快速测定,为研究肉制品中N-亚硝胺的测定提供了方法支持。
文摘为了揭示青花菜花球表面蜡粉代谢物的成分差异,以青花菜蜡粉缺失突变体和野生型为试材,基于气相色谱-质谱(gas chromatography tandem time-of-flight mass spectrometry,GC-TOF-MS)联用技术的非靶向代谢组学,对青花菜蜡粉缺失突变体和野生型的花球主要代谢通路及其产物进行深入分析,并采用单变量和多元变量统计分析及数据库注释筛选差异显著的代谢物。结果表明,青花菜花蕾蜡粉中共检测出显著差异代谢物24种,包括14种氨基酸类、4种有机酸类、1种脂肪酸类、1种胺类、1种糖类和3种其他类次生代谢物;其中,下调的有18种,包括了13种氨基酸类。综合富集分析和拓扑分析获得11条重要性凸显的代谢通路,其中差异最显著的代谢通路是氨基酸的生物合成,其次是次生代谢物的生物合成;而重要性最大的是色氨酸代谢。推测青花菜蜡粉缺失可以通过调节色氨酸代谢、次生代谢物生物合成以及氨基酸生物合成等途径,调节青花菜花蕾中氨基酸类和有机酸类等次生代谢产物的物质含量,进而调控花球的生长、营养品质以及耐寒性。
