Enalapril and Ramipril Selective Membranes*

Abstract

The construction and general performance characteristics of potentiometric plastic-membrane sensors for enalapril and ramipril drug-anions, are described. The electroactive materials are based on ion pair complexes between enalapril and ramipril anions, respectively, with Aliquot 336S cation. Both electrodes show near Nerstian response over the range 1 × 10−2 - 10−5 mol/L, with a detection limit of about 2.4 × 10−6 mol/L for enalapril and 6 × 10−6 mol/L for ramipril. The selectivity of the electrodes to a number of organic and norganic anions is reported. The electrodes proved useful in the determination of the active ingredient in their respective pharmaceutical preparations. The method is simple, rapid and does not require prior sample pre-treatment. * Presented in part at Euroanalysis IX, European Conference on Analytical Chemistry held on September 1-7, 1996 in Bologna, Italy