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BioMed Research International
Volume 2015 (2015), Article ID 697958, 13 pages
Research Article

Mass Spectral Profile for Rapid Differentiating Beta-Lactams from Their Ring-Opened Impurities

1School of Life Science, Beijing Institute of Technology, 5 Zhongguancun Street, South Haidian District, Beijing 100081, China
2Neuroscience Research Institute, Health Science Center, Peking University, Beijing 100191, China
3National Institutes for Food and Drug Control, Beijing 100050, China

Received 13 June 2014; Revised 1 September 2014; Accepted 7 October 2014

Academic Editor: Haiteng Deng

Copyright © 2015 Hecheng Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


High performance liquid chromatography tandem mass spectrometry (HPLC MS) has been widely used for β-lactam antibiotics determination. However, its application to identify impurities of these frequently used drugs is not sufficient at present. In this job, characteristic profiles of the collision induced dissociation (CID) spectra of both β-lactams and ring-opened β-lactams were extracted from the MS data of six β-lactam antibiotics and their forty-five impurities, and were confirmed by the MS data reported in the literature. These characteristics have been successfully applied to rapid differentiation of β-lactam and ring-opened β-lactam impurities in cefixime, cefdinir, and cefaclor. However, these characteristic profiles can only be obtained under low activating voltage. They did not display in the high energy activated CID spectra. Diagnostic fragmentations for determining the localization of double bond and substituents on the thiazine ring and the side chain were also observed. In addition, several characteristic fragmentations are hopeful to be used to differentiate the configurations of C-2 on the thiazine ring of ring-opened impurities, which is generally disadvantageous of mass spectrometry. Taken together, forty-five impurities were identified from the capsules of cefixime, cefdinir, and cefaclor.