A liquid chsomatographic-tandem mass spectrometric method was used to simultaneously determine four tobacco-specific nitrosamines in cigarette mainstream smoke.Cigarette smoke particulate,obtained under standardized m...A liquid chsomatographic-tandem mass spectrometric method was used to simultaneously determine four tobacco-specific nitrosamines in cigarette mainstream smoke.Cigarette smoke particulate,obtained under standardized machine smoking,was collected on a Cambridge filter pad.The particulate was co-extracted with citric acid-phosphate buffer and cyclohexane and further purified by solid-phase extraction.Analyte identification and quantification were performed using multiple reaction monitoring with one precursor ion and two product ions as identifiers and electrospray ionization in positive mode.The limits of detection were in the range of 0.05～0.24ng/mL using an injection volume of 20μL,linear range over 2.5～1000ng/mL,linear correlation coefficients above 0.998,and recoveries 90.2%～95.1%.展开更多
To study Saikosaponins in a Chinese traditional compound medicine by LC/MS. Saikosaponin A and D, which were the bioactive components of Bupleurum falcatum L., were not found in the medicine. And three isomeric compou...To study Saikosaponins in a Chinese traditional compound medicine by LC/MS. Saikosaponin A and D, which were the bioactive components of Bupleurum falcatum L., were not found in the medicine. And three isomeric compounds of Saikosaponin A and D were detected instead. Saikosaponin A and D were found have turned into two other isomers after treated by acid water, but keep unchanged when treated by neutral water. Two of the isomeric compounds which found in the Compound medicine were determined as Saikosaponin B1 and B2 . This work is helpful for quality control of the medicine and also is useful for supervising the procedures of manufacture.展开更多
目的采用LC/MSn技术推断拉氧头孢钠原料中杂质的结构。方法采用Shiseido TYPE UG80C18(4.6mm×250mm,5μm)色谱柱,以0.01mol/L醋酸铵溶液-甲醇(99:1,V/V)作为流动相A,以0.01mol/L醋酸铵溶液-甲醇(70:30,V/V)为流动相B,进行梯度洗脱...目的采用LC/MSn技术推断拉氧头孢钠原料中杂质的结构。方法采用Shiseido TYPE UG80C18(4.6mm×250mm,5μm)色谱柱,以0.01mol/L醋酸铵溶液-甲醇(99:1,V/V)作为流动相A,以0.01mol/L醋酸铵溶液-甲醇(70:30,V/V)为流动相B,进行梯度洗脱分离杂质。通过强力试验归属杂质的来源,在正离子模式下获取各杂质的质谱数据,结合头孢菌素的普遍质谱裂解规律和降解反应原理,解析相关杂质的结构。结果推断了12种杂质的化学结构,样品中未检出聚合物杂质。结论LC/MSn法可快速准确推断拉氧头孢钠原料中杂质结构,中国药典的拉氧头孢钠质量标准需要进一步提高。展开更多
文摘A liquid chsomatographic-tandem mass spectrometric method was used to simultaneously determine four tobacco-specific nitrosamines in cigarette mainstream smoke.Cigarette smoke particulate,obtained under standardized machine smoking,was collected on a Cambridge filter pad.The particulate was co-extracted with citric acid-phosphate buffer and cyclohexane and further purified by solid-phase extraction.Analyte identification and quantification were performed using multiple reaction monitoring with one precursor ion and two product ions as identifiers and electrospray ionization in positive mode.The limits of detection were in the range of 0.05～0.24ng/mL using an injection volume of 20μL,linear range over 2.5～1000ng/mL,linear correlation coefficients above 0.998,and recoveries 90.2%～95.1%.
文摘To study Saikosaponins in a Chinese traditional compound medicine by LC/MS. Saikosaponin A and D, which were the bioactive components of Bupleurum falcatum L., were not found in the medicine. And three isomeric compounds of Saikosaponin A and D were detected instead. Saikosaponin A and D were found have turned into two other isomers after treated by acid water, but keep unchanged when treated by neutral water. Two of the isomeric compounds which found in the Compound medicine were determined as Saikosaponin B1 and B2 . This work is helpful for quality control of the medicine and also is useful for supervising the procedures of manufacture.
文摘目的采用LC/MSn技术推断拉氧头孢钠原料中杂质的结构。方法采用Shiseido TYPE UG80C18(4.6mm×250mm,5μm)色谱柱,以0.01mol/L醋酸铵溶液-甲醇(99:1,V/V)作为流动相A,以0.01mol/L醋酸铵溶液-甲醇(70:30,V/V)为流动相B,进行梯度洗脱分离杂质。通过强力试验归属杂质的来源,在正离子模式下获取各杂质的质谱数据,结合头孢菌素的普遍质谱裂解规律和降解反应原理,解析相关杂质的结构。结果推断了12种杂质的化学结构,样品中未检出聚合物杂质。结论LC/MSn法可快速准确推断拉氧头孢钠原料中杂质结构,中国药典的拉氧头孢钠质量标准需要进一步提高。
