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
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.
