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 KTcO4 was 2 × 10–7 M and the slope of the electrode function at 20°C was 58 ± 1 mV/pTc $${\text{O}}_{4}^{ - }$$ . Potentiometric selectivity coefficients were determined for various anions. A correlation between the hydration energy ΔGhydr 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 Tc $${\text{O}}_{4}^{ - }$$ in the analyzed solution is 1 × 10–6–0.001 M. The behavior of the electrodes in strongly acidic solutions was studied.