Mass spectrometric approaches in structural characterization of cephalosporins.

The mass spectrometric behaviour of five structurally different cephalosporins has been studied in detail by means of different ionization/desorption methods (electron impact, fast atom bombardment, desorption chemical ionization, laser-induced vaporization) and metastable ion studies (linked scans and mass-analysed ion kinetic energy spectrometry). The best results were obtained by fast atom bombardment mass spectrometry, leading to both molecular ions and fragment ions diagnostic for structural identification.