Amitriptyline-molybdovanadate/-molybdotungstate based ion-selective membrane electrodes for determination of amitriptyline in pharmaceutical formulations and water samples

Abstract

Poly (vinyl chloride) membrane electrodes for the determination of amitriptyline hydrochloride were fabricated based on the use of amitriptyline-molybdovanadate and amitriptyline-molybdotungstate as electroactive materials and dioctylphthalate as the plasticizing agent. The effect of membrane composition on the electrode response was studied. The membrane electrodes containing amitriptyline-molybdovanadate (electrode A) and amitriptyline-molybdotungstate (electrode B) showed a fast and stable response over the amitriptyline hydrochloride concentration range 1.0×10−4–1.0×10−2molL−1. Under the optimum conditions, the slope of the calibration curve, and detection limits were found to be −36.2mV/decade; −40.81mV/decade and 6.87×10−5; 6.73×10−5molL−1, for electrodes A and B, respectively. The life span of both the electrodes was found to be more than 2months. The isothermal coefficient of electrodes A and B amounted to 0.00070V/°C and 0.00068V/°C, respectively. Both the electrodes were successfully applied to the determination of amitriptyline hydrochloride in tablets and water samples by direct potentiometric method.