Nitrate-Selective Electrode Developed by Electrochemically Mediated Imprinting/Doping of Polypyrrole

Richard S. Hutchins, Leonidas G. Bachas

Research output: Contribution to journalArticle

237 Scopus citations

Abstract

Nitrate-selective electrodes have been developed by electropolymerizing pyrrole onto glassy-carbon electrodes in the presence of NaNO3. Electrochemical variables were used to optimize the potentiometric response of the electrodes and to maximize the selectivity for nitrate over potentially interferent anions. Calibration plots with near-Nemstian slopes for nitrate were observed, -56 ± 1 mV/ decade (n = 18), over a linear range of four decades of concentration (5.0 × 10-5-0.50 M nitrate). The electrodes had detection limits of (2 ± 1) × 10-5 M nitrate (n = 18). The commercially available nitrate-selective electrodes suffer from interference by lipophilic anions, such as perchlorate and iodide. Compared to these electrodes, the polypyrrole-based nitrate electrodes demonstrated improved selectivity coefficients for perchlorate and iodide by as much as 4 orders of magnitude (KpotNO3-CIO4- = 5-7 × 10-2; KpotNO3-, I- = 5.1 × 10-2). An electrochemically mediated templating mechanism is proposed to explain the observed high selectivity for nitrate.

Original languageEnglish (US)
Pages (from-to)1654-1660
Number of pages7
JournalAnalytical Chemistry
Volume67
Issue number10
DOIs
StatePublished - Jul 1995
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry

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