DIFFERENTIAL-PULSE ADSORPTIVE STRIPPING VOLTAMMETRY OF THE DIURETIC TORASEMIDE AT A HANGING MERCURY DROP ELECTRODE

A method is described for the determination of torasemide, a loop diur etic, by differential-pulse adsorptive stripping voltammetry at a hang ing mercury drop electrode. Accumulation of this diuretic was found to be optimized in Britton-Robinson buffer (pH 2.50) solution with the f ollowing conditions: accumulation potential, -900 mV; accumulation tim e, 30 s; and rest time, 10 s. Under these conditions, the current show ed a linear dependence with concentration in the range 2.29 X 10(-7)-3 .65 x 10(-6) mol l(-1). The reproducibility, in terms of relative stan dard deviation, for 10 determinations of 4.89 x 10(-7) and 9.83 x 10(- 7) mol l(-1) solutions was 1.80 and 0.90%, respectively; the detection limit was 80 ppb (2.29 x 10(-7) mol l(-1)). The method was applied to urine samples spiked with torasemide, to obtain a recovery of 100.6 /- 3.4%.