Plastic Membrane Selective Electrode for Cetirizinium Ion Based on Cetirizinium-Tetraphenylborate Ion-Pair

Abstract

New cetirizinium (Cet) ion selective PVC membrane electrodes of both conventional and coated graphite types based on the ion-pair of cetirizine with tetraphenylborate are prepared. Both electrodes exhibited a mean calibration plot slope of 66.8 mV/(Cet) concentration decade, at 25 °C, within the concentration range 3.16×10–5–3.16×10–3 mol dm–3 Cet-HCl2. The change of pH within the range (1.5–2.8) for 1.0×10–3 mol dm–3and 1.0×10–4 mol dm–3solutions and (2.25–3.25) for 1.0×10–2 mol dm–3solution does not affect the electrode performance. Outside the working pH-ranges, the potential value decreases due to formation of diprotonated species on the acidic side and to formation of the free base on the alkaline side. The standard electrode potentials are determined at different temperatures and used to calculate the isothermal coefficient of the electrode (0.000875 V/°C). The electrode shows a very good selectivity for Cet-HCl2with respect to a large number of inorganic cations and sugars where selectivity coefficients ranging between 7.0×10–5and 3.1×10–3were obtained. The standard addition method is successfully applied to determine Cet-HCl2in pure solutions and in cetirizine dihydrochloride-containing tablets.