Simultaneous Determination of Orange G and Orange II in Industrial Wastewater by a Novel Fe2O3/MWCNTs-COOH/OP Modified Carbon Paste Electrode

A novel Fe 2 O 3 nano-materials/oxygen functionalized multi-walled carbon nanotubes/triton X-100 modified carbon paste electrode (Fe 2 O 3 /MWCNTs-COOH/OP/CPE) was prepared to simultaneously detect orange G (Or G) and orange II (Or II) by electrochemical methods. Compared with the bare carbon paste electrode (CPE), Fe 2 O 3 /MWCNTs-COOH/OP/CPE exhibited obvious electrocatalytic activities towards Or G and Or II. Furthermore, the two azo dyes were identified and separated successfully, and were simultaneously determined by the redox peaks in cyclic voltammograms (CVs) and differential pulse voltammogram (DPV) under optimum conditions. In DPV, anodic peak current (Ipa) and concentrations were linearly related well for 0.1-20.0   μM Or G and 0.2-50.0   μM Or II. The limits of detection (S/N   =   3) of Or G and Or II were 0.05   μM and 0.1   μM, respectively. Therefore, the electrode is suitable for the determination of Or G and Or II in industrial wastewater due to high sensitivity and selectivity, low detection limit, good reproducibility, as well as easy preparation and regeneration.