▎ 摘　　要

This paper describes a rapid and sensitive method for determination of the hair dye Basic Blue 41 in wastewater samples using screen-printed carbon electrodes modified with graphene (SPCE/Gr). The method is based on the reversible reduction of azo groups of the dye at potential of -0.23 V/-0.26 V, where both the anodic and cathodic currents increased 1,300% when compared to screen-printed carbon (SPCE) and glassy carbon electrodes (GCE). The optimization of a square wave voltammetric method was performed by means of 2(3) factorial design, Doehlert matrix and multi-response assays, and the best parameters were: frequency (54.8 Hz), step potential (6 mV), pulse amplitude (43.7 mV) and pH 4.5. The analytical curve was constructed from 3.00 x 10(-8) to 2.01 x 10(-6) mol L-1, with detection and quantification limits of 5.00 x 10(-9) and 1.70 x 10(-8) mol L-1, respectively. The repeatability of the method evaluated for 10 consecutive measurements at concentrations of 1.70 x 10(-7) mol L-1 and 1.70 x 10(-6) mol L-1, showed relative standard deviation of 3.56 and 0.57 %, respectively. The sensor based in SPCE/Gr was successfully applied in wastewater samples collected from a drinking water treatment plant and validated by comparison with HPLC-DAD method with good accuracy.