An oxalate oxidase electrode was constructed by immobilizing sorghum oxalate oxidase covalently on the surface of a polypropylene (PP) tip inserted in a Pt wire. Determination of oxalic acid was performed by oxidation of enzymatically generated H2O2 at 0.4 V Versus
Ag/AgCl. The biosensor showed optimal response within 30 s at pH 5.0 and 35 °C with a linear range of 0.028 to 0.4 mM. Biosensor measured oxalate in urine of healthy persons and urinary stone formers. The detection limit was 0.028 mM. Analytic recoveries of exogenously added oxalate in
urine (5 mg/L and 10 mg/L) were 94.5% and 90.2% respectively. Within and between batch coefficients of variation for urinary oxalate determination were < 5.1% and < 5.34% respectively. There was a good correlation (r = 0.96) between urinary oxalate values by standard enzymic method
and present method Enzyme electrode was used for more than 150 assays and had a storage life of 100 days at 4 °C. These results also conclude that polypropylene tube/sheet could be used as a solid support for immobilization of biomolecules for fabrication of biosensors.
The growing interest and activity in the field of sensor technologies requires a forum for rapid dissemination of important results: Sensor Letters is that forum. Sensor Letters offers scientists, engineers and medical experts timely, peer-reviewed research on sensor science and technology of the highest quality. Sensor Letters publish original rapid communications, full papers and timely state-of-the-art reviews encompassing the fundamental and applied research on sensor science and technology in all fields of science, engineering, and medicine. Highest priority will be given to short communications reporting important new scientific and technological findings.