Enzyme sensor system for determination of total cholesterol in fish plasma

An enzyme biosensor system was developed for rapid and continuous determination of total cholesterol in fish plasma.The system was constructed with an immobilized enzyme membrane, Clark-type oxygen electrode, flow system and personal computer.The enzyme membrane was prepared from cholesterol esterase, cholesterol oxidase, photosensitive polymer and an ultrathin dialysis membrane.The optimum assay conditions of the sensor system were established as follows: pH 6.8, temperature 25∞C and flow rate 0.2 mL/min.The calibration curves were linear in the range of 15-80 mg/dL for yellowtail, 17-42 mg/dL for amberjack and 20-70 mg/dL for rainbow trout.One assay was completed within 5 min and it was possible to determine the sample continuously.The sensor system was applied to the determination of total cholesterol in yellowtail plasma.A good correlation was observed between the values determined by the sensor method and the conventional method (correlation coefficient was 0.90).