Flow injection spectrophotometric determination of choline using immobilized enzymes

A flaw injection spectrophotometric method is described for the determinati on of choline based on the production of hydrogen peroxide from choline usi ng immobilized choline oxidase mini-column. The product is mixed downstream to oxidize iodide into tiiodide at an elevated pH in the presence of molyb denum (VI), and the absorbance of the triiodide was monitored at 352 nm The detection limit is lower than 0.01 mmol/L with relative standard deviation of 1.5% over the range 0.1-1.0 mmol/L. The sample throughput was 40/h.