In this work, a time-of-flight （TOF） mass spectrometer has been used to investigate the distribution of intermediate species and formation process of carbon clusters. The graphite sample was ablated by Nd：YAG laser...In this work, a time-of-flight （TOF） mass spectrometer has been used to investigate the distribution of intermediate species and formation process of carbon clusters. The graphite sample was ablated by Nd：YAG laser （532 nm and 1064 nm）. The results indicate that the maximum size distribution shifted towards small cluster ions as the laser fluence increased, which happened because of the fragmentation of larger clusters in the hot plume. The temporal evolution of ions was measured by varying the delay time of the ion extraction pulse with respect to the laser irradiation, which was used to provide distribution information of the species in the ablated plasma plume. When the laser fluence decreased, the yield of all of the clusters obviously dropped.展开更多
建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析卷烟主流烟气中中性化学成分的方法。以较长的弱极性柱HP-5MS(50 m×0.2 mm i.d.×0.33μm)作为第一维柱,较短的薄液膜中等极性柱DB-17MS(1.7 m×0.1 mm i.d....建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析卷烟主流烟气中中性化学成分的方法。以较长的弱极性柱HP-5MS(50 m×0.2 mm i.d.×0.33μm)作为第一维柱,较短的薄液膜中等极性柱DB-17MS(1.7 m×0.1 mm i.d.×0.1μm)作为第二维柱,对优质烟叶单料卷烟烟气的中性成分进行定性分析,经过人工纠错等分析初步鉴定出匹配度大于700的1 464种成分,重点讨论了中性香味羰基化合物全二维点阵的谱图特征,为烟气和复杂体系的深入研究提供了方法学基础。展开更多
采用高效液相色谱与四极杆飞行时间串联质谱(high performance liquid chromatography of quadrupole time of flight-tandem mass spectrometry,HPLC-Q-TOF-MS-MS)联用技术定性检测桑椹中多酚类物质,新鲜桑椹样品经体积分数80%丙酮溶...采用高效液相色谱与四极杆飞行时间串联质谱(high performance liquid chromatography of quadrupole time of flight-tandem mass spectrometry,HPLC-Q-TOF-MS-MS)联用技术定性检测桑椹中多酚类物质,新鲜桑椹样品经体积分数80%丙酮溶液超声辅助提取15 min后,采用C18固相萃取小柱分离纯化,纯化后的样品进行质谱鉴定。采用HPLC-Q-TOF-MS-MS对多酚进行分析:初步鉴定了桑椹中存在14种多酚类物质,主要以酚酸、花色苷和黄酮的形式存在。其中6种酚酸:3-O-咖啡酰奎宁酸、4-O-咖啡酰奎宁酸、二聚绿原酸、二聚4-O-咖啡酰奎宁酸、绿原酸顺式异构体、3,5-O-二咖啡酰基奎宁酸。4种花色苷:飞燕草-3-半乳糖苷、飞燕草-3-葡萄糖苷、矢车菊-3-葡萄糖苷、矢车菊-3-芸香糖苷;3种黄酮:芦丁、鞣花酸己糖苷和槲皮素3-O-(6’-O-丙二酰)葡萄糖苷,1种白藜芦醇衍生物。HPLC-Q-TOF-MS-MS可以鉴定出桑椹的多酚类物质。展开更多
建立了QuEChERS净化结合超高效液相色谱串联四级杆飞行时间质谱(UHPLC-Q-TOF/MS)法同时筛查猪肉中10种抗生素类兽药残留量的分析方法。样品经过Na;EDTA-Mcllvaine缓冲溶液-0.1%甲酸乙腈-NaCl-无水Na_(2)SO_(4)-C_(18)的提取净化。通过In...建立了QuEChERS净化结合超高效液相色谱串联四级杆飞行时间质谱(UHPLC-Q-TOF/MS)法同时筛查猪肉中10种抗生素类兽药残留量的分析方法。样品经过Na;EDTA-Mcllvaine缓冲溶液-0.1%甲酸乙腈-NaCl-无水Na_(2)SO_(4)-C_(18)的提取净化。通过Infinity Lab Poroshell 120 EC-C_(18)色谱柱分离,在正离子多反应监测模式下分析。结果表明,10种兽药相关系数大于0.99,在5.0~100.0μg/kg范围内线性关系良好,在5、10、20μg/kg三个添加水平下平均回收率为72.3%~117.3%,日内相对标准偏差为(Relative Standard Deviation,RSD)0.9%~10.4%,日间RSD为1.1%~13.4%,检测限(Limit of Detection,LOD)为0.25~1.0μg/kg,定量限(Limit of Quantity,LOQ)为0.5~5.0μg/kg。采用本方法对市场购买的50份新鲜生猪肉样品进行检测,1份样品四环素呈阳性,其余样品均未检出。该方法操作简便、快速,具有良好的精密度和定量限,适用于猪肉中10种抗生素类兽药的快速检测。展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB109005)National Natural Science Foundation of China(No.11175035)+2 种基金Chinesisch-Deutsches Forschungs Project(GZ768)the Fundamental Research Funds for the Central Universities of China(Nos.DUT12ZD(G)01,DUT14ZD(G)04)MMLab Research Project(DP1051208)
文摘In this work, a time-of-flight （TOF） mass spectrometer has been used to investigate the distribution of intermediate species and formation process of carbon clusters. The graphite sample was ablated by Nd：YAG laser （532 nm and 1064 nm）. The results indicate that the maximum size distribution shifted towards small cluster ions as the laser fluence increased, which happened because of the fragmentation of larger clusters in the hot plume. The temporal evolution of ions was measured by varying the delay time of the ion extraction pulse with respect to the laser irradiation, which was used to provide distribution information of the species in the ablated plasma plume. When the laser fluence decreased, the yield of all of the clusters obviously dropped.
文摘建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析卷烟主流烟气中中性化学成分的方法。以较长的弱极性柱HP-5MS(50 m×0.2 mm i.d.×0.33μm)作为第一维柱,较短的薄液膜中等极性柱DB-17MS(1.7 m×0.1 mm i.d.×0.1μm)作为第二维柱,对优质烟叶单料卷烟烟气的中性成分进行定性分析,经过人工纠错等分析初步鉴定出匹配度大于700的1 464种成分,重点讨论了中性香味羰基化合物全二维点阵的谱图特征,为烟气和复杂体系的深入研究提供了方法学基础。
文摘采用高效液相色谱与四极杆飞行时间串联质谱(high performance liquid chromatography of quadrupole time of flight-tandem mass spectrometry,HPLC-Q-TOF-MS-MS)联用技术定性检测桑椹中多酚类物质,新鲜桑椹样品经体积分数80%丙酮溶液超声辅助提取15 min后,采用C18固相萃取小柱分离纯化,纯化后的样品进行质谱鉴定。采用HPLC-Q-TOF-MS-MS对多酚进行分析:初步鉴定了桑椹中存在14种多酚类物质,主要以酚酸、花色苷和黄酮的形式存在。其中6种酚酸:3-O-咖啡酰奎宁酸、4-O-咖啡酰奎宁酸、二聚绿原酸、二聚4-O-咖啡酰奎宁酸、绿原酸顺式异构体、3,5-O-二咖啡酰基奎宁酸。4种花色苷:飞燕草-3-半乳糖苷、飞燕草-3-葡萄糖苷、矢车菊-3-葡萄糖苷、矢车菊-3-芸香糖苷;3种黄酮:芦丁、鞣花酸己糖苷和槲皮素3-O-(6’-O-丙二酰)葡萄糖苷,1种白藜芦醇衍生物。HPLC-Q-TOF-MS-MS可以鉴定出桑椹的多酚类物质。
文摘建立了QuEChERS净化结合超高效液相色谱串联四级杆飞行时间质谱(UHPLC-Q-TOF/MS)法同时筛查猪肉中10种抗生素类兽药残留量的分析方法。样品经过Na;EDTA-Mcllvaine缓冲溶液-0.1%甲酸乙腈-NaCl-无水Na_(2)SO_(4)-C_(18)的提取净化。通过Infinity Lab Poroshell 120 EC-C_(18)色谱柱分离,在正离子多反应监测模式下分析。结果表明,10种兽药相关系数大于0.99,在5.0~100.0μg/kg范围内线性关系良好,在5、10、20μg/kg三个添加水平下平均回收率为72.3%~117.3%,日内相对标准偏差为(Relative Standard Deviation,RSD)0.9%~10.4%,日间RSD为1.1%~13.4%,检测限(Limit of Detection,LOD)为0.25~1.0μg/kg,定量限(Limit of Quantity,LOQ)为0.5~5.0μg/kg。采用本方法对市场购买的50份新鲜生猪肉样品进行检测,1份样品四环素呈阳性,其余样品均未检出。该方法操作简便、快速,具有良好的精密度和定量限,适用于猪肉中10种抗生素类兽药的快速检测。
