CATHODIC STRIPPING VOLTAMMETRIC DETERMINATION OF PENTAMIDINE ISETHIONATE AT A HANGING MERCURY DROP ELECTRODE

Differential-pulse cathodic stripping voltammetry was used for the det ermination of trace amounts of pentamidine isethionate at a hanging me rcury drop electrode using its reduction peak at -1.57 V in 0.2 mol l- 1 sodium hydroxide. The optimum accumulation potential and accumulatio n time were -1.1 V and up to 180 s, respectively. Linear calibration g raphs were obtained up to 1 x 10(-6) mol l-1: the limit of detection w as calculated to be 3.0 x 10(-10) mol l-1. The effect of various compo nents 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 x 10(-7) mol l-1) in urine can be effec ted using a high dilution of the sample.