Naproxen ion-selective electrode and its application to pharmaceutical analysis.

An ion-selective membrane electrode was prepared based on ion-pair complex of naproxen with methyltrioctylammonium. Its basic analytical parameters such as: slope characteristics, measuring range, detection limit, response time, life time were determined. The electrode showed Nernstian response from the 10(-1) to 10(-4) mol l(-1) concentration range and 5.5-8.5 pH range, low limit of detection 5 x 10(-5) mol l(-1) and short response time--20s. Selectivity was good over a number of organic and inorganic anions. The electrode was applied for the determination of naproxen tablets in aqueous solutions by the calibration curve method and standard addition method.