Polymeric Membrane Ion‐Selective Electrode for Butyrylcholinesterase Based on Controlled Release of Substrate

Abstract

AbstractA butyrylcholine selective polymeric membrane electrode using o‐β‐cyclodextrin as ionophore is described as a reagent controlled‐release system for reagentless detection of butyrylcholinesterase. Butyrylcholine released across the membrane from inner filling solution of the ion selective electrode is consumed by reaction of the enzyme in sample solution and the concentration of butyrylcholine at the membrane surface can be sensed potentiometrically. The electrode with 0.01 M butyrylcholine in the inner solution yields a potential that varies linearly with butyrylcholinesterase concentration over the range of 0.0075–0.15 U mL−1 in 0.02 M of pH 7.4 sodium phosphate buffer solution. This approach can also be used to analyze butyrylcholinesterase inhibitors such as organophosphate pesticides. The inhibition percentage of parathion is proportional to its concentration in the range of 0.05–0.5 ng mL−1 with a detection limit of 0.03 ng mL−1.