Nitrate biosensors and biological methods for nitrate determination

•Nitrate determination is important in environmental materials.•Microbial Nitrate reduction coupled with spectrophotometry and chromatography.•Electrochemical determination of Nitrate allows real time analysis.•Nitrate reductase is used for fabrication of Nitrate biosensors.•Immobilization of Nitrate reductase using conducting or non-conducting polymers.

The inorganic nitrate (NO3‾) anion is present under a variety of both natural and artificial environmental conditions. Nitrate is ubiquitous within the environment, food, industrial and physiological systems and is mostly present as hydrated anion of a corresponding dissolved salt. Due to the significant environmental and toxicological effects of nitrate, its determination and monitoring in environmental and industrial waters are often necessary. A wide range of analytical techniques are available for nitrate determination in various sample matrices. This review discusses biosensors available for nitrate determination using the enzyme nitrate reductase (NaR). We conclude that nitrate determination using biosensors is an excellent non-toxic alternative to all other available analytical methods. Over the last fifteen years biosensing technology for nitrate analysis has progressed very well, however, there is a need to expedite the development of nitrate biosensors as a suitable alternative to non-enzymatic techniques through the use of different polymers, nanostructures, mediators and strategies to overcome oxygen interference.

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