Determination of uric acid in human saliva by capillary electrophoresis with electrochemical detection: potential application in fast diagnosis of gout

The clinical manifestations of gout result from the formation and deposition of uric acid (UA) crystals. The monitoring of UA level in less invasive biological samples such as saliva is suggested for diagnosis and therapy of gout, hyperuricemia and the Lesch-Nyhan syndrome. In order to investigate the correlation between trace amounts of UA in human saliva and urine and explore the potential application in fast diagnosis of gout, capillary electrophoresis with electrochemical detection (CE-ED) was applied for the determination of UA in human saliva and urine in this work. Under the optimum conditions, UA and three coexisting analytes could be well separated within 14 min at the separation voltage of 14 kV in 80 mmol L(-1) borax running buffer (pH 7.8). A good linear relationship was established between peak current and concentration of analytes over two orders of magnitude with detection limits (S/N = 3) ranging from 1.09 x 10(-7) to 5.0 x 10(-7) mol L(-1) for all analytes. This proposed method has been successfully applied for study of the correlation between the UA content of human saliva and urine, providing an alternative and convenient method for rapid diagnosis of gout.