β-Cyclodextrin-Based Potentiometric Sensors for Flow-Injection Determination of Acetylcholines

β-Cyclodextrins (β-CDs) based polyvinylchloride (PVC) and carbon paste (CPEs) electrodes were fabricated and applied for potentiometric determination of different acetylcholine (ACh) drevatives, namely; butrylcholine (BCh), acetylmethylcholine (AmCh) and acetylthiocholine (AtCh). Matrix composition optimization was done referring the effect of type and content of α-, β-, or γ-CDs, anionic sites and plasticizer. Electrodes incorporated with heptakis (2, 3, 6-tri-o-methyl)-β-CD as sensing ionophore, potassium tetrakis (4-florophenyl) borate (KTFPB) as anionic site and o-nitrophenyloctyl ether (o-NPOE) as electrode plasticizer showed the best electroanalytical performances. The fabricated electrodes worked satisfactorily in the concentration range from 10-6 to 10-2 mol L-1 with detection limit reaching 8.3×10-7 mol L-1 and fast response time of 2s. The developed sensors possessed improved selectivity, twords various acetylcholine derivatives rather choline. The sensors have been successfully applied for the potentiometric determination of ACh and its derivatives under flow injection analysis (FIA) and potentiometric titration conditions.