Abstract
The construction of plasticised PVC matrix-type scopolamine ion- selective membrane electrode and its use in the potentiometric determination of scopolamine in pharmaceutical preparations are described. It is based on the use of tlie ion-associate species, fonned by scopolainine cation and 5-nitrobarbitoric counter ion. The basic electrode peifonnance characteristics are evaluated according to IUPAC I-ecoininendatioiis. It exhibited a linear response for 1x10-2–1x10-5 M of scopolamine solutions with a cationic Nernstian slope over the pH range of 4-7. Common organic and inorganic cations showed negligible interference. Direct potentiometric determination of 1x10-2–1x10-5 M aqueous tubocurarine chloride using this membrane electrode system showed an average recovery of 99.05 with a mean standard deviation of 0.12. This electrode system was successfully applied to the potentiometric determination of scopolamine in some pharmaceutical preparations.