Selective and Rapid Biosensor Integrated into a Commercial Hand‐Held Instrument for the Measurement of Ammonium Ion in Sewage Effluent

Abstract

A disposable biosensor for ammonium ions in sewage effluent was developed and based on a screen‐printed carbon electrode coated with the enzyme glutamate dehydrogenase, 2‐oxoglutarate, and NADH. This rapid and selective amperometric biosensor is capable of detecting NH₄ ⁺ in sewage effluent at concentrations in the range 1–10 ppm. The biosensor was developed as a disposable, reagentless device incorporated into a fully automated, hand‐held instrument that can be used away from the laboratory. This low cost, commercially available system permits the measurement of NH₄ ⁺ in effluent samples in only 5 min and 20 s without any pretreatment. The results obtained correlated well with the standard laboratory method, used by the Environment Agency.