Spectrophotometric Determination of Uric Acid Based on Fading of o-Hydroxyhydroquinonephthalein-palladium(II)-hexadecyltrimethyl-ammonium Complex

A simple and highly sensitive spectrophotometric method for the determination of uric acid (UA) was established based on fading of the o-hydroxyhydroquinonephthalein-palladium(II)-hexadecyltrimethylammonium complex. In the determination of UA, Beer's law is obeyed in the range of 0.01 - 0.20 µg ml-1, with an effective molar absorptivity at 635 nm, the relative standard deviation being 6.5 × 105 dm3 mol-1 cm-1 and 1.5% (n = 5). This method is about 20-times more sensitive than the conventional methods. The method was successfully applied to the assay of UA in human urine.