Development of Nitrate-Selective Electrochemical Sensor with Integrated Micro-fluidics

This work describes the development and testing of a nitrate-selective electrochemical sensor using doped polypyrrole nanowires in a flow-through micro-fluidic. Doping of polypyrrole nanowires was performed galvanostatically in the presence of NaNO
₃
. Amperometry and flow-through analysis were performed to evaluate the sensor performance for determination of nitrate ions in two sets of calibration solutions (DI water and IAPSO standard seawater). The sensor response was linear over the range from 10 muM to 1 mM, with a sensitivity of 1.17-1.65 nA/muM and detection limit of (4.5 plusmn 1) muM. Compared to conventional nitrate-selective electrodes, which suffer from lipophilic interfering ions; this electrochemically doped PPy-NWs electrodes showed improved selectivity for chloride, sulfate, phosphate and perchlorates ions.