Rapid determination of nitrophenol isomers in polluted water based on multi-walled carbon nanotubes modified screen-printed electrode

A sensitive screen-printed electrode modified with multi-walled carbon nanotubes (MWCNTs/SPE) was applied to determine simultaneously m-nitrophenol, o-nitrophenol and p-nitrophenol. The electrochemical response showed that o-nitrophenol, m-nitrophenol and p-nitrophenol were entirely separated at the MWCNTs/SPE interface. Under the optimized conditions, it was found that the detection limits were 8.1×10 -8 , 5.5×10 -7 and 2.0×10 -7 M and the linear calibration ranges were 1.0×10 -6 ~1.9×10 -5 M, 2.5×10 -6 ~2.1×10 -5 M and 2.0×10 -6 ~2.0×10 -5 M for m-nitrophenol, o-nitrophenol and p-nitrophenol respectively, proving that the electrode presented here could be easily used to determine nitrophenol isomers simultaneously with high sensitivity within pH range from 4.8 to 8.0. The applications in water samples showed that no interferences appeared with deviations below 5% to the determination of nitrophenol isomers with 1000 fold excess, indicating a good response of this method for nitrophenol isomers detection. This disposable modified SPE combining with a portable electrochemical device were performed for wastewater samples on-field rapid determination.