Correspondence: C. S. Pundir, Biochemistry Research Laboratory, Department of Bio Sciences, Maharshi Dayarand University, Rohtak-124001, Haryara, India

We have reported the immmobilization of barley oxalate oxidase on to alkylamine glass beads through glutaraldehyde coupling (Pundir, C. S., Satyapal and Kuchhal, N. K. (1993) Clinical Chemistry 39, 1750–1751). The present report describes the immobilization of commercially available horseradish peroxidase on to zirconia-coated arylamine glass beads through diazotization and a new method for the discrete assay of urinary oxalate using both immobilized oxalate oxidase and peroxidase. In the method, urinary oxalate is precipitated with CaCl₂, redissolved in HCl and then assayed using immobilized enzymes. The oxalate in 24 h urine samples from apparently healthy male adults was measured by this method and found to be in the range of 12.2–28.0 mg with a mean of 19.8 mg. The percentage recovery of added oxalate (17.5 mg/l) was 96.7 ± 3.4 (mean ± SD). The mean value of urinary oxalate by our method is comparable with those obtained by the Sigma kit method. The cost of oxalate determination in 100 urine samples by the present method has been compared with that of the Sigma kit method.

Received 9 May 1997/17 September 1997; accepted 26 September 1997

© 1998 The International Union of Biochemistry and Molecular Biology