Fabrication of Electrochemiluminescence Biosensor of Polyphenol Oxidase and Its Analytical Application

Polyphenol oxidase in potato was extracted by ultrasonic induction in water suspension.The surpernatant layer was collected and mixed with pure graphite powder.The mixture,after air-drying and homogeneous grinding with liquid paraffin,was filled into hollow carbon rod.An electro-chemiluminescence (ECL) biosensor was thus prepared.This ECL biosensor was used for chemiluminescence (CL) detection of epinephrine through the CL reaction between luminol and hydrogen peroxide which was produced by oxidation of epinephrine via dissolved oxygen in the presence of polyphenol oxidase.Linear relationship was obtained between the magnitude of enhanced CL intensity and concentration of epinephrine in the range of 2×10-4-3×10-3g·L-1,with a detection limit of 6×10-5g·L-1.Precision of the method was tested at the concentration level of 4.0×10-4g·L-1,values of RSD′s (n=8) obtained were less than 5%.The proposed method was applied to the assay of epinephrine injections,giving results in consistency with the labelled values.Test for recovery was made by adding standard solution of epinphrine to the injection samples,and values of recovery found were in the range of 94%-99%.