An automated microfluidic colourimetric sensor applied in situ to determine nitrite concentration

A stand-alone sensor system with integrated sub-systems is demonstrated. The system is portable and capable of in situ reagent-based nutrient analysis. The system is based on a low cost optical detection method, together with an automated microfluidic delivery system that is able to detect nitrite with a limit of detection (LOD) of 15 nM. The sensor was operated in situ at Southampton Dockhead for 57 h (December 2010) and 375 measurements were taken.