Amineptine Plastic Membrane Electrode Based on its Ion Associate with Tetraphenylborate and Phosphomolybdic Acid

New amineptine hydrochloride (Am-Cl) ion-selective electrodes (conventional type) based on amineptinium-tetraphenylborate (I) and amineptinium-phosphomolybdate (II) were prepared. The electrodes exhibited mean slopes of calibration graphs of 57.9?mV and 53.8?mV per decade of (Am-Cl) concentration at 25?°C for electrodes (I) and (II), respectively. The electrodes can be used within the concentration range 3.16×10^?5?10^?2?M (Am-Cl) at a pH range of 2.0–3.9 for both electrodes. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficients of the electrodes, which were 0.00172?V?°C^?1 and 0.00091 V?°C^?1 for (I) and (II) electrodes, respectively. The electrodes showed a very good selectivity for (Am-Cl) with respect to a number of inorganic cations and sugars. The standard addition method is successfully applied to determine (Am-Cl) in pure solutions and in amineptine-containing tablets.