A rapid assay of identification for glimepiride and its cis-isomer by tandem mass spectrometry

A simple and rapid identification method of glimepiride and its cis-isomer was established for the first time. The collision-induced dissociation (CID) mass spectrometry method was used in this study. Under negative ion mode, the CID mass spectra of the deprotonated molecule ion showed two characteristic ions, m/z 364 and m/z 376, which are confirmed by the method of energy-resolved mass spectrometry (ERMS). The relative abundance of the m/z 364 of glimepiride showed lower than that of its cis-isomer, which is related to the stereo structure of glimepiride and its isomer. Zinc ion was chosen to adduct to the glimepiride and its isomer, which experimental results showed the zinc ions enhanced the degree of recognition. The R-Isomer values, which evaluate the degree of the isomer recognition, were investigated at different collision energy. The quantitative determination of glimepiride was performed by using MS/MS. Aiming at the recognition of geometric isomers; this methodology shows huge potential of extended mass spectrometry method to a large number of chiral drugs and their impurity.