Colorimetric, enzymatic, and liquid-chromatographic methods for serum uric acid compared

Abstract

We describe high-performance liquid chromatography in conjunction with electrochemical detection as a possible reference method for serum uric acid. Separation was effected on a column packed with "Vydac" strong anion-exchange resin, with use of a detection potential of +0.80 V vs. an Ag/AgCl reference electrode. Results were linearly related to concentration up to 1.0 g/liter, and no interferences were seen. Assay of human sera gave within-run and day-to-day coefficients of variation of 0.83% and 1.1%, respectively; analytical recoveries averaged 100%. Comparison of the new procedure (x) with the phosphotungstate and uricase methods (y) showed the following linear regression and correlation coefficients for results: y equal 0.963x + 0.219 (r = 0.995), and y = 0.991x + 0.165 (r = 0.999), respectively. As compared to these methods, the procedure we describe is more accurate, because of the selective detection system based on retention time and redox potential. Samples can be analyzed at the rate of 20/h. No deproteinization is required.