Electrochemical speciation analysis for simultaneous determination of Cr(iii) and Cr(vi) using an activated glassy carbon electrode

Lukas Richtera; Hoai Viet Nguyen; David Hynek; Jiri Kudr; Vojtech Adam

doi:10.1039/c6an00983b

Electrochemical speciation analysis for simultaneous determination of Cr(iii) and Cr(vi) using an activated glassy carbon electrode

Analyst. 2016 Oct 7;141(19):5577-85. doi: 10.1039/c6an00983b. Epub 2016 Jul 20.

Authors

Lukas Richtera¹, Hoai Viet Nguyen, David Hynek, Jiri Kudr, Vojtech Adam

Affiliation

¹ Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00 Brno, Czech Republic, European Union. vojtech.adam@mendelu.cz.

PMID: 27435634
DOI: 10.1039/c6an00983b

Abstract

In this study, the enhancement of electrochemical signals of Cr(iii) and Cr(vi) by using an activated glassy carbon electrode (GCE) measured by differential pulse voltammetry (DPV) is demonstrated. The activated GCE exhibited higher sensitivity for detection of Cr(iii) and Cr(vi) compared with the bare GCE. By using the activated GCE, the limit of detection decreased 15.3 times (from 0.230 to 0.015 μM) in the case of Cr(iii) determination and 75 times (from 9.000 to 0.120 μM) in the case of Cr(vi) determination. Moreover, a simultaneous speciation analysis of Cr(iii) and Cr(vi) using the activated GCE was presented. Scanning electron microscopy, elemental mapping, and electrochemical impedance spectroscopy were employed for investigation of the surface of the activated GCE. Finally, the influence of different ions (Na(+), K(+), NH4(+), SO4(2-), NO3(-), and Cl(-) in the form of Na2SO4, NaNO3, NH4Cl, and KCl salts) on the speciation signals of Cr(iii) and Cr(vi) in a mixture of the two Cr oxidation states was investigated.