Uric acid, enzymatic analysis

H.-L. Lee and S.-C. Chen, Microchip capillary electrophoresis with electrochemical detector for precolumn enzymatic analysis of glucose, creatinine, uric acid and ascorbic acid in urine and serum, Talanta, 64 (2004) 750-757. 

Diagnosis of renal problems, xanthinuria, and toxemia of pregnancy via determination of the ratio of hypoxanthine to xanthine in plasma is facilitated by the use of biosensors. Xanthine oxidase immobilized on aminopropyl-CPG (controlled pore glass) activated with glutaraldehyde oxidizes hypoxanthine first to xanthine and then to uric acid. Use of an IMER with biosensors for hypoxanthine, xanthine, and uric acid provides the necessary data. Pre- or postcolumn enzymatic reactions catalyzed by creatinine deiminase, urease, alkaline phosphatase, ATPase, inorganic pyrophosphatase, or arylsufatase facilitate analysis of uremic toxins (simultaneous detection of electrolytes, serum urea, uric acid, creatinine, and methylguanidine). 

For 15 N-measurements about 2 mg of pure uric acid were degraded by a modified Kjeldahl procedure and molecular nitrogen liberated for analysis of its isotope content by Li 0 Br (Ross and Martin, 1970) For 13 C-analysis uric acid was combusted according to Winkler and Schmidt (1980). Uric acid concentrations were measured enzymatically (Zailner, 1963). 

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