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The construction and general performance characteristics of ion-selective membrane electrodes sensitive to BF − 4 and ClO − 4 anions, respectively, are described. All electrodes show near-Nernstian responses in the range 10 −2 −10 −5 M . The selectivity of the electrodes to a number of organic and inorganic anions are reported. The electrodes are useful in the potentiometric determination of a few pharmaceutical preparations. The method is simple, rapid and does not require prior sample pre-treatment.

A simple potentiometric method is described for the rapid determination of nafronyl-drugs in pharmaceutical preparations such as tablets. Nafronyl ion-selective membrane electrodes with either the nafronyl-dipicrylamine ion-pair complex in 1,2-dichloroethane or the nafronyl-dinonylnaphthalenesulphonic acid ion-pair complex in a PVC matrix as electroactive materials were used. Both electrodes exhibit near-Nernstian responses to protonated-nafronyl activity from 10(-2) to about 10(-5)M, in pH ranges that depend on the nature of the electroactive material used in the membrane. Nafronyl in the mg-range can be determined by potentiometric titration with sodium tetraphenylborate solution, with a relative standard deviation of less than 2.0%. No interference from any excipients in the tablets was observed.