An Ion Selective Electrode for the Determination of Pertechnetate Ions

The electroanalytical characteristics of an ion-selective electrode (ISE) with a membrane based on a supramolecular polymer composition containing polyvinyl chloride, o-nitrophenyl octyl ether plasticizer, tetradecyphosphonium pertechnetate ionophore, and a lipophilic additive of tetradecylphosphonium tetraphenyborate are studied. The limit of detection for the ISE in aqueous solutions containing KTcO(4)was 2 x 10(-7)M and the slope of the electrode function at 20 degrees C was 58 +/- 1 mV/pTcO(4)(-). Potentiometric selectivity coefficients were determined for various anions. A correlation between the hydration energy Delta G(hydr) and selectivity coefficients calculated by the method of mixed solutions is observed. It was found that a change in the pH of the solution in the range 2-12 slightly affects the electrode potential when the concentration of TcO4- in the analyzed solution is 1 x 10(-6)-0.001 M. The behavior of the electrodes in strongly acidic solutions was studied.