Effect of humic acid on the underpotential deposition-strippingvoltammetry of copper in acetic acid soil extract solutions atmercaptoacetic acid-modified gold electrodes

• Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bareand modified gold electrodes in 0.11M acetic acid, the first fraction of the European Union’s Bureau Communautaire de Références (BCR)sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showedhigher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acidsolutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l−1 of humic acid, themercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayerformed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of thehumic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modifiedelectrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic resultsyielded the straight-line equation y (g l−1) = 1.10x − 44 (ppb) (R = 0.992, n = 6), indicating good agreement between the two methods.

Ämnesord

NATURVETENSKAP  -- Kemi -- Analytisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Analytical Chemistry (hsv//eng)

Nyckelord

Underpotential deposition-stripping voltammetry; Modified gold electrode; Mercaptoacetic acid; Acetic acid; Copper; Humic acid

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)