Electrochemical reduction of cefminox at the mercury electrode and its voltammetric determination in urine

The electrochemical behaviour of cefminox in phosphate buffers solutions over pH range 2.0–9.0 using differential-pulse polarography, DC-tast polarography, cyclic voltammetry and linear sweep voltammetry (staircase) has been studied. In acidic media, a non reversible diffusion-controlled reduction involving two electrons occurs and the mechanism for the reduction was suggested. A differential-pulse polarographic method for the determination of cefminox in the concentration range 5.8×10−6–6.0×10−5 M with a detection limit of 1.76×10−6 M was proposed. Also, a method based on controlled adsorptive pre-concentration of cefminox on the hanging mercury drop electrode followed by linear sweep voltammetry, allows its determination in the concentration range 8.3×10−8–1.5×10−6 M with a detection limit of 2.47×10−8 M. These methods have been used for the direct determination of cefminox in human urine with recoveries between 98 and 103%, and precision around ±2%.