Development of micro-fluidic nitrate-selective sensor based on doped-polypyrrole nanowires

• Published in: Sensors and actuators. B, Chemical Vol. 132; no. 2; pp. 623 - 630
• Main Authors: Aravamudhan, Shyam, Bhansali, Shekhar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 16-06-2008
• Subjects: Electrochemical; Ion-selective electrodes; Micro-fluidics; Nanostructures; Nanostructures; Micro-fluidics; Ion-selective electrodes; Electrochemical
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2008.01.046

This paper presents a flow-through, nitrate-selective, electrochemical sensor developed by electropolymerization (doping) of polypyrrole nanowire (PPy-NW) electrodes. The flow-through micro-fluidic platform enabled a realistic and controlled testing environment. Cyclic voltammetry, 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
μM (0.14
ppm Nitrate-N) to 1
mM (14
ppm Nitrate-N), with a sensitivity of 1.17–1.65
nA/μM and detection limit of 4.5
±
1
μM or 0.063
±
0.014
ppm Nitrate-N. The electrochemically doped PPy-NW electrodes show improved selectivity for chloride, sulfate, phosphate and perchlorate ions, without the loss from interfering ions.