An initial-rate potentiometric method for the determination of uric acid using a fluoride ion-selective electrode

The principle of a general potentiometric method based on Emerson-Trinder reaction for the assay of various hydrogen peroxide generating systems is reported. Emerson-Trinder reaction, habitually employed as a spectrophotometric indicator reaction, is exploited in this method as a potentiometric indicator reaction. This method is based on the detection of F⁻ ions, liberated from the oxidation of a fluorophenol compound used as hydrogen-donor in Emerson-Trinder reaction, by a fluoride ion-selective electrode. The ability and usefulness of this method are illustrated by an initial-rate potentiometric determination of uric acid in aqueous and human serum samples, for which, initial-rate reaction progress curves, linear calibration curve, within-day precisions, upper and lower detection limits, and also its analytical recovery were reported.