Polarographic and voltammetric determination of trace amounts of 2-aminoanthraquinone

2-Aminoanthraquinone (2-AA) is a genotoxic intermediate in the industrial synthesis of anthraquinone dyes. In this work, electroanalytical methods based on two-electron reduction of anthraquinone at mercury electrodes were developed for determination of microto nanomolar concentrations of this analyte in mixed aqueous-methanol media. Calibration plots obtained for differential pulse voltammetry and direct current voltammetry at a hanging mercury drop electrode exhibited a sigmoidal shape within the analyte's concentration range of (1-500) × 10^-7 mol L^-1, presumably because of strong adsorption of the analyte at the electrode surface. Linearity of the calibration plots was achieved for higher concentrations of 2-AA at a conventional dropping mercury electrode using DC tast polarography and differential pulse polarography, with limit of quantitation of 4 × 10^-6 mol L ^-1 in Britton-Robinson buffer (pH 6)-methanol mixture (1:1). Adsorption of 2-AA on the electrode surface enabled its determination at nanomolar concentrations (limit of quantitation 2.8 × 10^-9 mol L^-1) using cathodic adsorptive stripping voltammetry in Britton-Robinson buffer (pH 2)-methanol mixture (99:1).