Chemometrically-Assisted Fabrication of a Potentiometric Sensor for Potassium Ion Based on Kryptofix 22 Ionophore

A novel ion-selective membrane electrochemical sensor based on Kryptofix 22 as an ionophore was constructed for determination of potassium ion in real samples. The D-optimal mixture design (D‑OMD) was used as an experimental design strategy for optimal formulation of the membrane ingredients. The fabricated electrode exhibits a Nernstian slope of 59.80 ± 0.65 mV per decade and a linear range of 1.0 × 10–4 to 1.0 × 10–1 mol/L with respect to potassium ion at the pH range of 3.0 to 7.0 and its detection limit was found to be 6.2 × 10–5 mol/L. The response of the electrode is very stable and it exhibits a good reproducibility with a fast response time (~10 s). The experimental results, showed a good selectivity towards the K+ ion at present of interfering ions. The obtained results by using D-OMD showed a non-linear relation between the slope of the electrode and its ingredients. The proposed electrode was successfully applied for determination of potassium ion in vegetables and urine samples.