Recent developments in electroanalytical chemistry of cephalosporins and cefamycins

Cephalosporins (I, R-4 = H) and cefamycins (I, R-4 = OCH3) are antibiotics with a broad spectrum of antimicrobial and antibacterial properties. These compounds contain a -lactam ring which is fused with a six-membered dihydro thiazine ring bearing substituents R-1 and R-2 in the side-chains at C-3 an d C-7 (I)(Tabie 1). They are available either as free acids (R-3 = H) or sa lts (R-3 = Na or Li). During the last two decades electroanalytical techniq ues were used or proposed for sensitive and selective determinations of a n umber of these antibiotics. Advantage of these procedures for analyses of drugs and biological material is that they often do involve only limited or no pre-separation, which wou ld not only be time-consuming but also a possible source of errors. Nevertheless, the majority of reported studies was based on an empirical ch oice of conditions for recording of current-voltage curves. To achieve a pr oper and most efficient use of electroanalytical methods it is necessary - perhaps even more importantly than for other analytical techniques - to und erstand at least the principles of the nature of the processes involved. In the majority of published papers either the question of the nature of the electrode process yielding the measured current was not mentioned or only g uesses were made without sufficient experimental evidence.