Electroanalytical sensing of nitrite at shallow recessed screen printed microelectrode arrays

We demonstrate that unmodified screen printed shallow recessed graphite microelectrode arrays can be used for the sensing of nitrite in aqueous solutions. The screen printed arrays comprise 6 microdiscs which have radii of 116 (+/- 6) microns and are recessed by 4 microns and separated by 2500 microns from their nearest neighbour in a hexagonal arrangement. The screen printed arrays permit the low micromolar sensing of nitrite in aqueous solutions via cyclic voltammetry with the assessable linear range and detection limit further reduced through the application of amperometry. The protocol is shown to be feasible for the sensing of nitrite in river water samples at levels indicated by the World Health Organisation. The disposable nature and low cost of the sensor offer an economical and portable screening tool for nitrite.