Quinidine ion-selective electrode for potentiometric determinations in pharmaceutical preparations

Abstract

The construction and evaluation of a quinidine ion-selective electrode, without an inner reference solution, based on an ion exchanger [quinidine tetrakis(4-chlorophenycol)borate] dissolved in 2-nitrophenyl octyl ether and immobilized in PVC is described. The prepared electrode showed a linear response in the concentration range 3 × 10 −5-1 × 10 −2 M in quinidine, with a slope of 57.5 mV per decade when the ph of the solutions was between 5 and 7.5. The reproducibility of the electrode was approximately ±1 mV during a day's work, with a response time of less than 10 s for quinidine concentrations between 10 −4 and 10 −2 M. The electrode was used for the direct potentiometric determination of quinidine in a pharmaceutical preparations, giving results with an average recovery of 100.7% and a mean standard deviation of 2.3%