Enhanced Measurement Stability and Selectivity for Choline and Acetylcholine by Capillary Electrophoresis with Electrochemical Detection at a Covalently Linked Enzyme-Modified Electrode

Abstract

Enzyme-modified microelectrodes were developed for the indirect amperometric detection of acetylcholine and choline following separation by capillary electrophoresis. Electrodes were prepared by first sequentially electrodepositing polypyrrole and polytyramine from the monomers on a 200-microm platinum electrode. The polymer bilayer provides enhanced selectivity and pendant amino groups for covalent coupling of acetylcholinesterase (AChE) and choline oxidase (ChO) by their reaction with glutaraldehyde. The AChE/ChO-modified electrode was then employed as an end-column detector to determine acetylcholine and choline with and without the internal standard butyrylcholine. Excellent operational stability during 2 days of continuous use was observed, with detection limits of 2 microM or 50 fmol for both acetylcholine and choline. The response from potential interferences, such as dopamine, catechol, and norepinephrine, were significantly reduced in comparison to a bare platinum electrode. The utility of this approach was demonstrated by monitoring the uptake of choline into synaptosomes.

Effect of (R)-Salsolinol and N-Methyl-(R)-Salsolinol on the Balance Impairment Between Dopamine and Acetylcholine in Rat Brain: Involvement in Pathogenesis of Parkinson Disease

“…org/content/vol54/issue4). The pmPD layer functions as a permselective coating on the electrode (21 ), and the pTy layer provides pendant amino groups for covalent attachment of AChE and ChO through a glu-taraldehyde linker (22 ). We then used the AChE-ChO/ pmPD/pTy-or ChO/pmPD/pTy-modified electrode as the working electrode.…”

A Dual‐Electrode Approach for Highly Selective Detection of Glucose Based on Diffusion Layer Theory: Experiments and Simulation

“…[1][2][3] Glucose oxidase (GOD)-modified working electrodes are usually used for the purpose of specific response in the detection of glucose. Although the oxidation of glucose by GOD is highly specific, the detection principle of such a biosensor-usually the amperometric detection of the formed H 2 O 2 -is largely unspecific and, therefore, highly sensitive towards side reactions caused by chemical impurities.…”

A new microdialysis-electrochemical device for in vivo simultaneous determination of acetylcholine and choline in rat brain treated with N-methyl-(R)-salsolinol

“…The polymer pmPD could restrict the permeability of small organic molecules such as ascorbic acid and urate, while retaining a high permeability to small species like H 2 O 2 . The PTy layer facilitates the immobilization of enzymes by providing pendant amino groups (Inoue et al, 2002). The cyclic voltammogram for electrodeposition of pTy polymer (Fig.…”

“…Electropolymerization of pmPD can produce a thin non- . The PTy layer provides pendant amino groups for covalent attachment of enzymes through a glutaraldehyde linker (Inoue et al, 2002;Miscoria et al, 2006).…”