Determination of camazepam and bromazepam in human serum by adsorptive stripping voltammetry

Abstract

Adsorptive stripping voltammetry was used for the determination of trace amounts of the benzodiazepines camazepam and bromazepam. This very sensitive method is based on controlled adsorptive pre-concentration of the drugs on the hanging mercury drop electrode. Measurements were taken by differential-pulse voltammetry after determination of the optimum accumulation conditions. The response was linear in the range 3 × 10^–9–9 × 10^–9M(270 s and-0.60 V for the pre-concentration) for camazepam and 1 × 10^-8–8 × 10^–8M(90 s and-0.40 V) for bromazepam. In the concentration ranges investigated, the relative standard deviation was lower than 6%. The method is applicable to the determination of the drugs in human serum, with detection limits of 20 ng ml^-1 of serum (30 s and-0.62 V for the pre-concentration) for camazepam and 200 ng ml^–1 of serum (10 s and-0.41 V) for bromazepam.