Enzyme‐modified carbon paste: Tetrathiafulvalene electrodes for the determination of acetylcholine

The response characteristics of a new sensor for determining acetylcholine are reported. The sensor is based on a carbon paste electrode containing the enzymes acetylcholinesterase and choline oxidase and the electron transfer mediator tetrathiafulvalene (TTF). TTF is shown to efficiently reoxidize the reduced flavin adenine dinucleotide centers of choline oxidase. Acetylcholine calibration graphs are obtained in the range 10−6 to 10−3 M in pH 7.0 phosphate buffer, and the sensors are shown to operate efficiently at low applied potentials, where electrochemical interference due to oxidation of ascorbic acid is minimized.