A new cucurbit[6]uril-based ion-selective electrode for acetylcholine with high selectivity over choline and related quaternary ammonium ions

Abstract

Detection of acetylcholine (ACh(+)) with high sensitivity and selectivity in the presence of interfering ions including choline (Ch(+)) poses a significant analytical challenge. A cucurbit[6]uril derivative, (allyloxy)(12)CB[6], forms a stable 1:1 inclusion complex with ACh(+) but does not interact significantly with Ch(+) in solution. Based on this result, we prepared ion-selective electrodes (ISEs) for ACh(+) using (allyloxy)(12)CB[6] as an ionophore. The (allyloxy)(12)CB[6]-based ISEs detect ACh(+) with unprecedentedly high selectivity over Ch(+) as well as other interfering ions such as dopamine, NH4+, N(CH3)(4)(+) and N(CH2CH3)(4)(+).