Organically nanoporous silica gel based on carbon paste electrode for potentiometric detection of trace Cr(III)

Anal Chim Acta. 2009 Aug 11;647(2):210-4. doi: 10.1016/j.aca.2009.06.007. Epub 2009 Jun 10.

Abstract

A new ion-selective electrode (ISE) for the detection of trace chromium(III) was designed by using 2-acetylpyridine and nanoporous silica gel (APNSG)-functionalized carbon paste electrode (CPE). The presence of APNSG acted as not only a paste binder, but also a reactive material. With 7.5 wt% APNSG proportions, the developed electrode exhibited wide dynamic range of 1.0 x 10(-8) to 1.0 x 10(-3) M toward Cr(III) with a detection limit of 8.0 x 10(-9) M and a Nernstian slope of 19.8 +/- 0.2 mV decade(-1). The as-prepared electrode displayed rapid response (approximately 55 s), long-time stability, and high sensitivity. Moreover, the potentiometric responses could be carried out with wide pH range of 1.5-5.0. In addition, the content of Cr(III) in food samples, e.g. coffee and tea leaves, has been assayed by the developed electrode, atomic absorption spectrophotometer (AAS) and atomic emission spectrometer (ICP-AES), respectively, and consistent results were obtained. Importantly, the response mechanism of the proposed electrode was investigated by using AC impedance and UV-vis spectroscopy.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Carbon / chemistry*
  • Chromium / analysis*
  • Coffee / chemistry
  • Electric Impedance
  • Electrodes
  • Gels / chemistry*
  • Hydrogen-Ion Concentration
  • Ions / chemistry
  • Plant Leaves / chemistry
  • Potentiometry / methods*
  • Pyridines / chemistry
  • Sensitivity and Specificity
  • Silicon Dioxide / chemistry*
  • Spectrophotometry, Ultraviolet
  • Tea / chemistry

Substances

  • Coffee
  • Gels
  • Ions
  • Pyridines
  • Tea
  • Chromium
  • 2-acetylpyridine
  • Carbon
  • Silicon Dioxide