APPLICATION OF NITRITE REDUCTASE FROM ALCALIGENES-FAECALIS S-6 FOR NITRITE MEASUREMENT

The enzymatic reaction of nitrite reductase (NIR) from Alcaligenes fae calis S-6 was applied to the measurement of nitrite. NIR was immobiliz ed on the surface of a gold electrode using filter paper and a dialysi s membrane, and used as a working electrode in a three-electrode syste m. Amperometric methods were applied using NIR and the electron mediat or l-methoxy PMS (1-methoxy-5-methylphenazinium methylsulfate). The de crease in cathodic current showed a correlation to nitrite concentrati on over the range 0-1 mg/l. Measurements using a batch-flow type syste m gave a lower detection limit of 0.01 mg/l. This is sufficient for th e detection of nitrite in natural waters. (C) Published by Elsevier Sc ience Limited.