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

The electrochemical behaviour of D isperse R ed 13 dye at a glassy carbon electrode was investigated in both organic and aqueous organic mixtures. Best results were obtained in N , N ‐dimethylformamide/ B ritton–Robinson buffer (1:1, v/v), which displays a well‐defined peak at ‐0.40 V ( vs A g/ A g C l) owing to reduction of the protonated nitro group. This method can be successfully applied to the electroanalytical determination of D isperse R ed 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 D isperse R ed 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. D isperse R ed 13 was successfully determined in textile industry wastewater by means of the proposed method after pre‐extraction in a solid‐phase extraction cartridge.