The measurement of choline and acetylcholine by means of HPLC, a post-column enzyme reactor, and electrochemical detection has been simplified and optimised. The use of a cation exchanger and enzyme reactor fitted in a cartridge holder appeared to result in reproducible, sensitive, and selective measurement of endogenous choline and acetylcholine with a lower detection limit of 50 fmole.

Determination of acetylcholine and choline in the femtomole range by means of HPLC, a post-column enzyme reactor, and electrochemical detection

A simple, efficient, economic, and sensitive method is presented for the detection of choline and acetylcholine in neuronal tissue using HPLC, a postcolumn enzyme reactor with immobilized enzyme, and electrochemical detection. The method is based on a separation of choline and acetylcholine by cation exchange HPLC followed by passage of the effluent through a postcolumn reactor containing a mixture of acetylcholinesterase and choline oxidase; the latter enzyme converts choline to betaine and hydrogen peroxide, the former enzyme hydrolyzes acetylcholine to acetate and choline. The hydrogen peroxide produced is electrochemically detected. A simple and efficient preparation of neuronal tissue is described using an optional prepurification step on Sephadex G-10 columns, offering the possibility to detect choline and acetylcholine as well as catecholamines and their related metabolites in the same tissue sample. The sensitivity of the assay system is 250 fmol for choline and 500 fmol for acetylcholine.

A simple, sensitive, and economic assay for choline and acetylcholine using HPLC, an enzyme reactor, and an electrochemical detector.

Determination of acetylcholine and choline in perchlorate extracts of brain tissue using liquid chromatography-electrochemistry with an immobilized-enzyme reactor.

C. Eva

Papers

Acetylcholine measurement by high-performance liquid chromatography using an enzyme-loaded postcolumn reactor