Selective and rapid biosensor integrated into a commercial hand-held instrument for the measurement of ammonium ion in sewage effluent

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. Copyright © Taylor & Francis Group, LLC