CONSTRUCTION AND CHARACTERIZATION OF NITRATE REDUCTASE-BASED AMPEROMETRIC ELECTRODE AND NITRATE ASSAY OF FERTILIZERS AND DRINKING-WATER

The construction and characterization of a nitrate reductase-based amp erometric electrode for determination of nitrate ion is described. The electrode consisted of nitrate reductase held by dialysis membrane on to a Nation-coated glassy carbon electrode. Methyl viologen was allowe d to absorb into the Nation layer, which acted as a reservoir for the electron mediator. The utility of the electrode to assay fertilizer an d water sample for nitrate was demonstrated. The assays conducted with this electrode compared well with colorimetric and potentiometric ass ays of the same samples.