AMPEROMETRIC DETERMINATION OF FISH FRESHNESS BY A HYPOXANTHINE BIOSENSOR

The traditional determination of fish freshness is to detect total vol atile basic nitrogen, microbial load or hypoxanthine. These methods ar e complex and expensive. A hypoxanthine biosensor was constructed by u sing immobilised xanthine oxidase and a platinum electrode. The enzyme was immobilised on a silk membrane. The electrode detected the hydrog en peroxide released during the enzymatic reaction. A linear range fro m 0.05 to 100 x 10(-6) M of hypoxanthine was observed. When the method was applied to fish samples, the results obtained agreed well with th ose obtained by the conventional total volatile basic nitrogen and mic robial load. This biosensor provides a reliable, simple, rapid and eco nomical method for the measurement of fish freshness.