Simple and rapid measurement of acetylcholine and choline by HPLC and enzymatic-electrochemical detection.

A simple, rapid and sensitive method for the detection of acetylcholine and choline in tissue extracts is reported. Acetylcholine and choline are first separated by HPLC then react in a mini-column with acetylcholinesterase and choline oxidase immobilized on Sepharose. The resulting H(2)O(2) produced by choline oxidase is then detected electrochemically. The assay is more sensitive than existing methods. We believe that the principle involved in this method namely the combination of immobilized enzymes and the high sensitivity of electrochemical detection may be applied to other substances that can be converted by immobilized enzymes into an electrochemically detectable compound.