Sensitive method for HPLC determination of acetylcholine, choline and their analogues using fluorometric detection

A method is described for reversed-phase HPLC separation of acetylcholine and choline and of their homologues in tissue extracts or perfusion fluids, combined with postcolumn enzymatic derivatization and fluorometric quantification. The separation occurs on a polymeric resin derivatized with hydrophobic moiety and the mobile phase consists of Na2HPO4, 3-(p-hydroxyphenyl)propionic acid and sodium dodecylsulphate; postcolumn enzyme reactor contains immobilized acetylcholinesterase, choline oxidase, and peroxidase. The limits of detection are 1 pmol choline and 3 pmol acetylcholine per sample. The method is free of interferences encountered with electrochemical detection and well suited for non-attended automatic operation.