title: Internal standard method for the measurement of choline and acetylcholine by capillary electrophoresis with electrochemical detection.
abstract: An internal standard method has been developed for the determination of the neurotransmitter acetylcholine and/or its metabolic precursor choline. This approach couples the high separation efficiency of capillary electrophoresis with the sensitivity and selectivity of electrochemical detection at an enzyme-modified electrode. Indirect electrochemical detection is accomplished at a 25 microm platinum electrode modified by cross-linking the enzymes choline oxidase and acetylcholinesterase with glutaraldehyde. Although in this simple form of electrode fabrication there is a gradual loss of response from the electrochemical detector with time, accurate quantitation is achieved by the addition of butyrylcholine, which is also a substrate for acetylcholinesterase, as an internal standard. A linear response is achieved between 0 and 125 microM with a limit of detection of 2 microM (25 fmol). The utility of this method was demonstrated by monitoring the kinetics of choline uptake in synaptosomal preparations.
authors.affiliation: Department of Chemistry, College of Arts & Sciences, University of Toledo, Toledo, OH 43606-3390, USA.
authors.forename: Dana D
authors.initials: DD
authors.lastname: Wise
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Barkhimer
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Brault
authors.forename: Jon R
authors.initials: JR
authors.lastname: Kirchhoff
authors.forename: William S
authors.initials: WS
authors.lastname: Messer
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hudson
mesh_terms: D000109:Acetylcholine / Q000032:analysis* / Q000378:metabolism; D000818:Animals; D002794:Choline / Q000032:analysis* / Q000378:metabolism; D004563:Electrochemistry / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012015:Reference Standards; D013574:Synaptosomes / Q000378:metabolism
chemical_list: D002794:Choline; D000109:Acetylcholine