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Improvement of Amperometric Sensor Used for Determination of Nitrate with Polypyrrole Nanowires Modified Electrode
State Key Laboratory of Chemical Engineering, Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
Chemistry Department of Dezhou University, Dezhou, Shandong 253011, China
* Author to whom correspondence should be addressed.
Received: 2 September 2005; Accepted: 12 December 2005 / Published: 16 December 2005
Abstract: Polypyrrole(PPy) nanowire modified electrodes were developed by template-freeelectrochemical method based on graphite electrode. The modified electrode wascharacterized by their amperometric response towards nitrate ions. Before reduction ofnitrate ions, electrochemical solid-phase extraction (EC-SPE) of nitrate in/on modifiedelectrodes was conducted. It is found that the unusual nanowired structure of polypyrrolelayer (instead of well known cauliflower structure) allows us to increase the effectivesurface area of the electrode and subsequently the sensitivity. And the effects ofelectrochemical preparation parameters of PPy nanowire modified electrodes on theircorresponding characters were evaluated. The experimental results show that theelectrochemical preparation parameters of the modified electrodes such as scan rate,polymerization potential, temperature of polymerization solution and polymerization timehave significantly effects on the morphology of PPy nanowires and subsequently effectivesurface area of the electrode and electroreduction current density of nitrate. Thedetermination sensitivity may be varied according to the modification parameters. Under acertain polymerization conditions, the corresponding sensitivity reaches 336.28 mA/M cm2 and the detection limit is 1.52×10-6 M. The proposed method was successfully applied in thedetection of nitrate in the real samples.
Keywords: Amperometric sensor; Polypyrrole Nanowires; Modified electrode; Nitrate determination
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Zhang, X.-L.; Wang, J.-X.; Wang, Z.; Wang, S.-C. Improvement of Amperometric Sensor Used for Determination of Nitrate with Polypyrrole Nanowires Modified Electrode. Sensors 2005, 5, 580-593.
Zhang X-L, Wang J-X, Wang Z, Wang S-C. Improvement of Amperometric Sensor Used for Determination of Nitrate with Polypyrrole Nanowires Modified Electrode. Sensors. 2005; 5(12):580-593.
Zhang, Xiu-ling; Wang, Ji-xiao; Wang, Zhi; Wang, Shi-chang. 2005. "Improvement of Amperometric Sensor Used for Determination of Nitrate with Polypyrrole Nanowires Modified Electrode." Sensors 5, no. 12: 580-593.