Reproterol plastic membrane ion-selective electrodes based on its individual and mixed ion-exchangers with phosphotungstic and/or phosphomolybdic acids

Reproterol hydrochloride (RpCl), selective PVC membranes based on ion assoc iates of reproterolium-phosphotungstate (Rp-PTA); reproterolium-phospho-mol ybdate (Rp-PMA) or a mixture of both (Rp-PTA/PMA) were prepared. Tbe electr odes displayed a linear response over the concentration range of 6.3 x 10(- 6)-1.0 x 10(-1) mol dm(-3) RpCl. The working pH ranges of the above electro des were 2.5-9.0, 2.5-8.5 and 2.0-9.0 and their isothermal temperature coef ficients were 0.00014, 0.00090 and 0.00103 V/degreesC, respectively. The el ectrodes showed good selectivity to the reproterolium ion with respect to m any inorganic cations, sugars and amino acids. The standard additions and p otentiometric titration methods were used to determine RpCl in pure solutio ns and in its pharmaceutical preparations with high accuracy and precision. (C) 2001 Elsevier Science B.V. All rights reserved.