DETERMINATION OF CEFOBID USING ADSORPTIVE STRIPPING VOLTAMMETRIC TECHNIQUE IN DIFFERENT MEDIA

A sensitive voltammetric method has been developed for the cephalosporin antibiotic, cefoperazone monosodium salt (cefobid). The method is based on controlled adsorptive preconcentration of cefobid on the hanging mercury drop electrode (HMDE), followed by voltammetric determination of the surface species by cathodic stripping voltammetry. Cyclic voltammetry was used to examine the interfacial behavior of the drug. The electroanalytical techniques used were direct current stripping voltammetry (DCSV) and differential pulse stripping voltammetry (DPSV). The adsorptive stripping response was evaluated with respect to preconcentration dependence, possible interferences, and other variables. The drug is strongly adsorbed in acidic media, with maximum adsorption at pH2. The detection limit found by DPSV was 2 X 10(-9) M (1.33 ppb), with 240 second preconcentration. The relative standard deviation at the 1 X 10(-7) M level was 3.2%. The interference of uric and ascorbic acids and copper and calcium ions has been studied. The method was applied to the determination of cefobid in urine.