[An enzyme electrode biosensor for inosine determination].

An enzyme electrode biosensor was used for the amperometric determination of inosine in its tablets by co-immobilizing nucleoside phosporylase and xanthine oxidase on a hydrogen peroxide electrode. As a fundamental electrode the hydrogen peroxide electrode has an advantage of stability in analysis compared with the 02 electrode. The enzyme electrode showed a linear response to inosine in the range of 1-268 mg/L with a response of 60 seconds under a sample injection volume of 25 microL. Based on the enzyme electrode, inosine solutions were determined with an average recover rate of 100.8% and a relative standard deviation (RSD) of les than 0.14% in 20 assays. The lifetime of the enzyme electrode was relative long and could be used continuously at 25 degrees C for 25 days. These results demonstrated that the enzyme electrode biosensor could be used to determine inosine and its derivatives specifically, rapidly, conveniently and economically.