Determination of Fe(III) in wine samples using a ruthenium oxide hexacyanoferrate modified microelectrode

• The electrocatalytic reduction of Fe(III) using a modified microelectrode is reported.
• Fe(III) is electrocatalytically reduced at 0.0 V without interference from Fe(II).
• The amperometric determination of Fe(III) was performed in different wine samples.

The electrocatalytic reduction of Fe(III) was investigated using a carbon fibre microelectrode modified with a ruthenium oxide hexacyanoferrate film (RuOHCF/CFM). At surfaces containing this chemical modifier, Fe(III) is electrocatalytically reduced at 0.0 V without interference from Fe(II), hence allowing the speciation of Fe(III). A linear relationship between the cathodic current and concentration of Fe(III) was obtained by amperometry in the range 10–210 μmol L−1 with detection and quantification limits of 0.22 (S/N = 3) and 0.74 (S/N = 10) μmol L−1, respectively. The described amperometric method was successfully applied for the determination of Fe(III) in different wine samples.