Anion-selective electrodes based on solidified 1,3-dihexadecylimidazolium ionic liquids with halide and pseudohalide anions

- We developed ion-selective electrodes (ISEs) using solidified ionic liquids (ILs).
- ISEs based on ILs containing Cl-, I- and SCN- are sensitive to respective anions.
- ISE selectivity is high and drastically differs from Hofmeister series.

In this study screen-printed solid-state electrodes using low-melting ionic liquids with cation of 1,3-dihexadecylimidazolium and such anions as chloride, iodide, and thiocyanate were developed. Potentiometric response and electrochemical characteristics of ion-selective electrodes in KCl, KI, and KSCN solutions were studied. All sensors exhibited sensitivity toward the corresponding anions, the slopes close to Nernstian ones, low detection limits (3.0 ∙ 10− 6 M for SCN−), and high selectivity in the presence of the extraneous anions. Operation time of the sensors was not less than one year. The applicability of the developed electrodes for the potentiometric determination of iodide in pharmaceuticals and thiocyanate in human saliva was demonstrated.