孟鲁司特多级质谱分析

Multi-stage Mass Spectral Analysis of Montelukast

目的研究孟鲁司特在ESI正离子模式下的质谱行为,并对其主要碎片进行归属。方法注射泵直接进样分析孟鲁司特标准品溶液,然后对准分子离子和分子离子谱中的基峰,在离子阱内进行碰撞诱导解离。结果与结论在ESI正离子模式下,孟鲁司特主要以[M+H]+形式存在,经碰撞诱导解离,依次失去H2O、CO2和含硫的支链,得到比较稳定的碎片离子m/z 422,其在更高的能量下,发生多种重排,得到复杂的子离子质谱图。

OBJECTIVE To study the fragmentation behaviors of montelukast in positive ESI mode and assign the main ions in their mass spectra. METHODS A syringe pump was used for the direct loop injections of standard solutions and then the quasi-molecular ion of montelukast and each base-peak in a mass spectrum were selected for further multi-stage analyses. RESULTS and CONCLUTION In positive ESI mode, the [M＋ H]^＋ ion was the most abundant peak in full scan MS. After collision induced dissociation（CID）, successive losses of H2O, CO2 and a side chain containing sulphur atom were observed and a very stable ion at m/z 422 was obtained, which underwent further fragmentation at a higher energy. At last, the complex daughter ions of m/z 422 were obtained.