PREPARATION OF A CHOLESTEROL OXIDASE ENZYME REACTOR AND ITS APPLICATION FOR THE DETERMINATION OF TOTAL CHOLESTEROL IN DIFFERENT FOOD PRODUCTS WITH A FIA SYSTEM

Abstract

An immobilized enzyme reactor was prepared for determination of cholesterol with amperometric flow injection (FIA) technique. The immobilization of cholesterol oxidase was studied on glass, Acrylex C-IOO polymer and on alkylamino-bonded silica beads. The activated loads were packed into a glass column. The hydrogen peroxide formed in the enzyme reaction was determined by electrochemical detection. Glutaraldehyde-activated alkylamino silica seems to be the best means for enzyme immobilization. The mode of immobilization, the effects of linked enzyme units on activity, pH, temperature and stability of the enzyme reactor were also investigated. Total cholesterol in different food materials was measured by the optimized FIA system. The accuracy and reproducibility of the FIA method developed was compared to the conventional GC measurement. The results show that the described FIA method is also suitable for cholesterol determination in food products.