Preparation of a cimetidine ion-selective electrode and its application to pharmaceutical analysis.

A novel cimetidine ion-selective electrode is prepared, characterized and used in pharmaceutical analysis. The electrode incorporates PVC-membrane with cimetidine-phospohotungstate ion pair complex. The electrode exhibits a Nernstian response for cimetidine in the concentration range 1.0 x 10(-5)-1.0 x 10(-2) M with a slope of 58+/-1 mV per decade. The limit of detection is 5.0 x 10(-6) M. The electrode displays a good selectivity for cimetidine with respect to a number of common foreign inorganic and organic species. It can be used in the pH range 3.0-5.5. The membrane sensor was successfully applied to the determination of cimetidine in its tablets as well as its recovery from a urine sample.