Rapid nitrate detection system based on ion selective electrode

A fluidic control system for detecting the nitrate content in solution rapidly was presented. The nitrate ion selective electrodes were prepared by electrochemically mediated imprinting doping of polypyrrole. Calibration was first performed using a sequence of nitrate solutions of 10-1 M, 10-3 M and 10-4 M, delivered by miniature pump and valves to a test chamber where nitrate ion selective electrodes were mounted. The calibration time was 4.5 minutes while the actual test time for one nitrate solution sample was only 90 seconds. It was found that the potential difference per decade concentration change in the ion selective electrode was a constant from 10-4 M to 10-1 M of nitrate concentrations. Based on the potentiometric response, the nitrate detection limit was found to be about 10-4 M. This low-cost, rapid nitrate contamination detection system could be used for soil and drinking water measurement.