Electrochemical method for quantitative determination of trace amounts of disperse dye in wastewater

Abstract

The electrochemical behaviour of Disperse Red 13 dye at a glassy carbon electrode was investigated in both organic and aqueous organic mixtures. Best results were obtained in N,N-dimethylformamide/Britton–Robinson buffer (1:1, v/v), which displays a well-defined peak at -0.40 V (vs Ag/AgCl) owing to reduction of the protonated nitro group. This method can be successfully applied to the electroanalytical determination of Disperse Red 13 in a very simple and inexpensive way. All the differential pulse voltammetry parameters were optimised by using a glassy carbon electrode modified with poly(glutamic acid) films. The targeted analytical method presented a linear response from Disperse Red 13 concentrations between 2.5 × 10−7 and 3 × 10−6 mol l−1 (r = 0.997), with a detection limit of 1.5 × 10−8 mol l−1 and recoveries of 89.7–95.10% in water samples. Disperse Red 13 was successfully determined in textile industry wastewater by means of the proposed method after pre-extraction in a solid-phase extraction cartridge.