Identification and Fragmentation of Cefalosporins, Lincosamides, Levofloxacin, Doxycycline, Vancomycin by ESI-MS

The aim of the paper is the identification of the most frequently used antibiotics such as cefazolin, cefuroxime, cefotaxime, ceftriaxone, ceftazidime, lyncomycin, clindamycin, levofloxacin, doxycycline and vancomycin by electrospray ionization mass spectrometry interface in positive and negative modes. The fragmentation pathways of the group of antibiotics were colligated on the basis of the obtained ESI mass spectra. Generally, the positive ion spectra of antibiotics are higher in intensity including an [M+H]⁺ ion and producing less fragmentation as well as more informative compared to the negative ion spectra. Only ESI of levofloxacin in positive and negative modes with the chosen tune parameters leads to degradation of molecular ion, so the parent ion does not appear in the mass spectra. The group of antibiotics (cephalosporins and lincosamides) shows the same characteristic fragmentation. These setup parameters were successfully applied for the routine determination of antibiotics in their pharmaceutical dosage forms and other objects. Data base was developed for identification of antibiotics by comparison of their molecular and fragment ions.