Cathodic stripping voltammetric determination of pentamidine isethionate at a hanging mercury drop electrode

Abstract

Differential-pulse cathodic stripping voltammetry was used for the determination of trace amounts of pentamidine isethionate at a hanging mercury drop electrode using its reduction peak at –1.57 V in 0.2 mol l^–1 sodium hydroxide. The optimum accumulation potential and accumulation time were –1.1 V and up to 180 s, respectively. Linear calibration graphs were obtained up to 1 × 10^–6 mol l^–1: the limit of detection was calculated to be 3.0 × 10^–10 mol l^–1. The effect of various components of urine on the voltammetric response was studied, and albumin, creatinine and uric acid caused interference in the method. The direct determination of the drug (>1 × 10^–7 mol l^–1) in urine can be effected using a high dilution of the sample.