A NOVEL ENZYME SENSOR FOR THE DETERMINATION OF INORGANIC-PHOSPHATE

A new, highly sensitive enzyme sensor was developed for the determinat ion of inorganic phosphate using maltose phosphorylase, acid phosphata se, glucose oxidase and mutarotase. The combination of the first two e nzymes generates two glucose molecules per reaction cycle and recycles one molecule of phosphate. Finally, the oxidation of glucose is catal ysed by mutarotase and glucose oxidase. The four enzymes were coimmobi lized on a regenerated cellulose membrane which was mounted on the tip of a platinum amperometric electrode for the detection of enzymatical ly formed hydrogen peroxide. Thus, a detection limit of 10(-8) M was o btained and the sensor response was linear in the range 0.1-1 mu M, wh ich is relevant for the monitoring of water pollution.