A selective cholesterol biosensor blased on composite film modified electrode for amperometric detection

An amperometric cholesterol biosensor based on immobilization of cholesterol oxidase in a Prussian blue (PB)/polypyrrole (PPy) composite film on the surface of a glassy carbon electrode was fabricated. Hydrogen peroxide produced by the enzymatic reaction was catalytically reduced on the PB film electrode at 0 V with a sensitivity of 39 mu A (mol/L)(-1). Cholesterol in the concentration range of 10(-5) similar to 10(-4) mol/L was determined with a detection limit of 6 x 10(-7) mol/L by amperometric method. Normal coexisting compounds in the bio-samples such as ascorbic acid and uric acid do not interfere with the determination. The excellent properties of the sensor in sensitivity and selectivity are attributed to the PB/PPy layer modified on the sensor.