Sensitive electrochemical detection of toxic nitro-phenol in real environmental samples using enzymeless oxidized-carboxymethyl cellulose-sulfate/sulfated polyaniline composite based electrode

Abstract In current study, sulfated-polyaniline and oxidized-sulfated-carboxymethyl cellulose (S-Pani/Ox/CMCS) deposited on a glassy carbon electrode (GCE) was investigated in a mediator-free, non-enzymatic electrochemical sensing for ortho-nitrophenol (2-NP). The resulting S-Pani/Ox/CMCS bio-composites were analyzed by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and X-ray photoelectron. The electrode detection limit, sensitivity, and pH effect on the performance of the fabricated sensor were evaluated by using different electrochemical methods including differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. The –OH, -SO3, and –COO- groups present in Ox/CMCS verified it could act as an brilliant substrate for polymerization and adsorption of aniline. Under optimal conditions of Ox/CMCS concentration in the fabricated S-Pani/Ox/CMCS bio-composite, the signal and the logarithm of 2-NP concentration showed a linear correlation, and a very low detection limit of 0.05 μM was observed. The S-Pani/Ox/CMCS modified GCE confirmed high reproducibility, good stability, and durability was found applicable to the detection of 2-NP in milk, water, and orange juice samples. The obtained result for the fabricated sensor revealed that it was highly selective for the detection of 2-NP, which might play a significant role in human health protection and environmental monitoring applications.