A novel biosensor system for the determination of phosphate

A highly sensitive biosensor system has been developed for phosphate detection. This biosensor system is based on the pyruvate oxidase reaction and a subsequent luminol chemiluminescence reaction. Hydrogen peroxide generated by pyruvate oxidase reacts with luminol catalyzed by an immobilized peroxidase. The resulting chemiluminescence is detected by a photomultiplier. This system uses a flow injection analysis (FIA) system resulting in the rapid determination of phosphate, taking approximately 3 min for one measurement. A linear response was observed from 0.37 mu M to 7.4 mu M phosphate while the detection limit was 74 nM. This sensitivity is sufficient to determine the maximum permissible phosphate concentration of the natural waters of Japan (0.32 mu M). The pyruvate oxidase immobilized column gave a stable response over a period of 2 weeks when stock solutions were analyzed.