Simplified urinary oxalate determination using an enzyme electrode.

An enzyme electrode for urine oxalate measurement has been produced using acrylamide gel-entrapped oxalate decarboxylase retained over a CO2 sensor. Urine required pre-treatment with EDTA, but oxalate extraction was not necessary and inhibition by phosphate and sulphate was not apparent until after 10-14 days. The linear range was 0-0.2 mmol/l. Analysis of 50 urine specimens diluted 1 in 10 in pH 3.0 glycine buffer showed good correlation with a widely-used colorimetric method (y = 1.101x-0.018, r = 0.955).