Application of adsorptive stripping voltammetry for determination of selected methoxyimino cephalosporins in urine...

In last two decades different electroanalytical methods are used for sensitive and selective determination of cephalosporins. In this paper the electrochemical behavior of methoxyimino cephalosporins, reduction mechanism and nature of the process at the mercury electrode surface is presented. Special attention is paid to the cephalosporins adsorption at the mercury surface. Based on this phenomenon, the adsorptive stripping methods are established for determination of low concentration of these drugs in urine samples, both in-vitro, and in-vivo conditions. The application of the adsorptive stripping differential pulse voltammetry (AdSDPV) for determination of cefpodoxime proksetile (CP), cefotaxime (CF), desacetylcefotaxime (DCF) and cefetamet (CEF) is summarized. The best sensitivity of determination in-vitro in urine was achieved for CP, in acid solutions (LOD 7.410(-9)M and LOQ 2.410(-8)M), followed by CF, CEF and DCF. This is in accordance with the strength of their adsorption. Determination of CF and DCF by AdSDPV in-vivo is also presented. Compared to other analytical methods, AdSDPV showed advantages in simplicity of the sample preparation, and over the other voltamperometric methods, higher sensitivity and selectivity.