Plastic membrane selective electrode for cetirizinium ion based on cetirizinium-tetraphenylborate ion-pair

New cetirizinium (Cet) ion selective PVC membrane electrodes of both conven tional and coated graphite types based on the ion-pair of cetirizine with t etraphenylborate are prepared. Both electrodes exhibited a mean calibration plot slope of 66.8 mV/(Cet) concentration decade, at 25 degrees C, within the concentration range 3.16 x 10(-5)-3.16 x 10(-3) mol dm(-3) Cet-HCl2. Th e change of pH within the range (1.5-2.8) for 1.0 x 10(-3) mol dm(-3) and 1 .0 x 10(-4) mol dm(-3) solutions and (2.25-3.25) for 1.0 x 10(-2) mol dm(-3 ) solution does not affect the electrode performance. Outside the working p H-ranges, the potential value decreases due to formation of diprotonated sp ecies on the acidic side and to formation of the free base on the alkaline side. The standard electrode potentials are determined at different tempera tures and used to calculate the isothermal coefficient of the electrode (0. 000875 V/degrees C). The electrode shows a very good selectivity for Cet-HC l2 with respect to a large number of inorganic cations and sugars where sel ectivity coefficients ranging between 7.0 x 10(-)5 and 3.1 x 10(-3) were ob tained. The standard addition method is successfully applied to determine C et-HCl2 in pure solutions and in cetirizine dihydrochloride-containing tabl ets.