Properties of ion-selective electrodes with polymeric membranes for ketoprofen determination

The aim of the research was to create electrodes based on PVC membrane with solid contact. The membranes were plasticized with bis(2-ethylhexyl)sebacate, (DOS), dibutylphthalate (DBP) diisobutylphthalate (DIBP), tris(2-ethylhexyl) phosphate (TEHP), and 2-nitrophenyloctyl ether (o-NPOE) in which the active substance tetraoctylammonium 3-benzoyl-α-methylbenzeneacetate (KET-TOA) was dissolved. The basic analytical parameters of the ketoprofen electrode such as measuring range, detection limit, response time, lifetime, and selectivity coefficients for some organic and inorganic anions were determined. For all electrodes similar potentiometric responses were obtained: measuring range 1 × 10−4 −1 × 10−1 M, and Nernstian slope of characteristics of about 55–60 mV/decade. The electrode was used to determine ketoprofen in the synthetic sample and pharmaceutical preparations, in injections, tablets and capsules in the concentration range of 0.025–25 mg/mL in aqueous solution at pH 5.5–8.5.