Isomer differentiation and structural characterization of penem β-lactam antibiotics by mass-analyzed ion kinetic energy spectrometry
✍ Scribed by Pradip R. Das; B. N. Pramanik; V. M. Girijavallabhan; A. K. Ganguly
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 416 KB
- Volume
- 26
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
A number of clinically significant penem &lactams, both free acids and sodium salts, were investigated by massanalyzed ion kinetic energy spectrometry (MIKES) following fast atom bombardment (FAB) ionization. The collisionally activated dissociation (CAD) products of [M + HI + and [M + Nal' ions are described. Carbon dioxide loss was observed for some of the free acids, whereas a daughter ion generated by PIactam ring cleavage was characteristic of the sodiated species. Other fragments included successive cleavages and rearrangements of the substituent sidwAdn, permitting complete characterization of these chains. The fragmentation pattern for both protonated and sodiated species were more clearly established by CAD MIKES than by normal FAB mass spectral analyses. A notable feature of this technique was its ability to differentiate between pairs of regioisomeric penems on the basis of their fragmentation patterns. These compounds could not be differentiated in the lsual mass spectra.