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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.

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A high-performance capillary electrophoretic (CE) method with electrochemical detection (ED) has been developed for determination of the pharmacologically active flavonoids in Ginkgo biloba L. and phytopharmaceuticals containing its extract. Epicatechin, catechin, rutin, apigenin, luteolin, and quercetin are important flavonoids in this plant. Operated in a wall-jet configuration, a 300 micro m diameter carbon-disk electrode was used as working electrode with good response to the six analytes at +1000 mV (relative to the SCE). Under the optimum conditions, the analytes were separated within 22 min in a borax buffer (pH 9.0). Excellent linearity was obtained over two orders of magnitude and detection limits (S/N=3) ranged from 1.4 x 10(-7) to 5.0 x 10(-7) g mL(-1) for all six analytes. The method was successfully used for assay of Ginkgo biloba L. and its phytopharmaceuticals after a relatively simple extraction procedure; the results obtained were satisfactory.

A simultaneous determination of trans-resveratrol, (-)-epicatechin, and (+)-catechin in red wine by capillary electrophoresis with electrochemical detection (CE-ED) is reported. The effects of the potential of the working electrode, pH and concentration of running buffer, separation voltage, and injection time on CE-ED were investigated. Under the optimum conditions, the analytes could be separated in a 100 mmol/L borate buffer (pH 9.2) within 20 min. A 300 microm diameter carbon disk electrode has a good response at +0.85 V (vs SCE) for all analytes. The response was linear over 3 orders of magnitude with detection limit (S/N = 3) ranging from 2 x 10(-7) to 5 x 10(-7) g/mL for all analytes. This method has been used for the determination of these analytes in red wine without enrichment, and the assay result was satisfactory.