A novel method for the detection of nitrate was developed using simplified nitrate reductase (SNaR) that was produced by genetic recombination techniques. The SNaR consists of the fragments Mo-molybdopterin binding site and the nitrate reduction active site and has high activity for nitrate reduction. Controlled potential coulometry using an indium tin oxide (ITO) thin layer electrochemical cell and UV-Vis spectroscopy were combined for nitrate reduction and nitrite monitoring. Reduction of nitrate to nitrite was performed in the thin layer cell using methyl viologen (MV2+/MV+.) as the electron transfer mediator for SNaR. Nitrite was then measured spectroscopically after its reaction with Griess reagents to form a colored product, which is proportional to the concentration of nitrate in the sample. The nitrate sample solution required for analysis is less than 500 �L. Under optimal conditions, the linear range of the nitrate response was determined as 1-160 �M, with a sensitivity of 8000 AU M-1. Results for the determination of nitrate concentration in several natural water samples using this device are in good agreement with analysis done with a standard method. 

Simplified nitrate reductase based nitrate detection method by thin layer controlled potential coulometry and Griess reaction

246th National Meeting (2013)

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