Determination of free and total cholesterol in human bile samples using an enzyme electrode

A reliable cholesterol electrode was assembled with a Clark type oxygen electrode and cholesterol oxidase immobilised on a nylon net fixed on the electrode surface. Determination of free (unesterified) and total (esterified and unesterified) cholesterol in human bile samples was performed. Results were compared with the enzymatic-spectrophotometric procedure based on the Roeschlau method. The electrode has a usable life of more than two weeks, and more than 300 determinations could be performed. The CV values for free and total cholesterol in bile samples is 5-6%. The comparison between the proposed procedure and the spectrophotometric procedure is fair for the half of the results (delta less than 5%) and acceptable in the other half (delta less than 25%).