摘要
应用液相色谱-质谱联用技术建立了快速分离鉴定头孢丙烯及合成中间体7-氨基-3-[烯丙-1-基]-3-头孢环-4-羧酸(7-APRA)Z/E异构体的方法。7-APRA去氢离子在二级质谱中均发生丢失H2S和OCNH的碎裂反应,产生碎片离子m/z161和m/z152。由于7-APRAZ异构体能发生氢转移,从而促使H2S丢失,故Z异构体产物离子丰度比(I161/I152)明显高于E异构体,这一特征可以用于异构体的质谱识别。类似地,由于头孢丙烯Z异构体易断裂,因此更容易形成含有稳定苯酚基团的m/z 205碎片离子。为了给实验结果提供理论支持,使用密度泛函理论(DFT)量子计算对7-APRA异构体的构型进行优化,并对可能的碎裂机理进行探讨。
A method of liquid chromatography-mass spectrometry was developed for separa- tion and differentiation of the Z/E isomers of bulk cefprozil and its intermediate substance （ 6R, 7R ）-7-amino-8-oxo-3-（ 1-propenyl ）-5-thia-l-azabicyclo E 4. 2. 0 ] oct-2-ene-2-carboxylic acid （γ-APRA）. For the 7 APRA isomers, both of the deprotonated molecules are favorable to undergo fragmentation via losing H2S and OCNH, and give the product ions at the m/z 161 and m/z 152, respectively. Different to the E isomer, the Z isomer of 7-APRA is facile to undergo γ-H migration, which promotes the H2S elimination. As a result, Z-7-APRA has the significantly higher abundance ratio of [I161/I152] than the E isomer, which can be used for isomer differentiation. Analogously, the deprotonated cefprozil Z isomer is also more favorable to undergo dissociation to form the ion of m/z 205, due to thephenol function group in the structure. Furthermore, their fragmentation mechanisms were proposed, and the density functional theory （DFT） calculations were employed to consist with the experimental results.
出处
《质谱学报》
EI
CAS
CSCD
北大核心
2014年第3期262-268,共7页
Journal of Chinese Mass Spectrometry Society
基金
浙江省科技厅分析测试科技计划项目(2013C37055)资助
关键词
头孢丙烯
异构体
区分
液质联用
负离子
cefprozil
isomer
differentiate
liquid chromatography-mass spectrometry （LC- MS）
negative ions
