Abstract
Three new potentiometric membrane sensors responsive to procainamide hydrochloride (PR) were constructed and their general performance characteristics were determined. The sensors were constructed from PR ion-association complexes with tetraphenylborate (NaTPB) (1), phosphomolybdic acid (PMA) (2) and phosphotungstic acid (PTA) (3) as exchange sites in a polyvinyl chloride (PVC) matrix. The sensorsexhibitedstable, rapid and-near-Nernstian properties for PR at concentrations of 1 x 10(-2)-4 x 10(-6), 1 x 10(-2) -5 x 10(-6), 1 x 10(-2)-6 x 10(-6) M at 25 degrees C with cationic slopes of 58 +/- 0.5, 57 +/- 0.5 and 56 +/- 0.5 (mV/decade) for sensor 1, 2 and 3 respectively. The response time of the sensors was 20s in the optimum pH range of 4-8. The sensors were used in steady state and flow injectionmode (automated system). Method validation revealed the sensors have high selectivity, lowdetection limits, long life, wide dynamic ranges as well as high accuracy and precision. Direct determination of 5-2000 mu g/ml of PR in solution returned average recoveries of 98.5%, 99.0% and 98.5% andmean relative standard deviations of 1.6%, 1.6% and 1.8% at 200.0 mu g/ml for sensor 1, 2 and 3 respectively. Further, detection of procainamide in spiked urine exhibited favorable relative standard deviation (1.601.76%) and high recovery (98.83-99.26%). The sensors were used as end-point indicators for titration of procainamide with NaTPB.