Reduced graphene oxide nanosheets modified with nickel disulfide and curcumin nanoparticles for non-enzymatic electrochemical sensing of methyl parathion and 4-nitrophenol.

A method was designed for simultaneous voltammetric determination of methyl parathion pesticide (MP) and 4-nitrophenol (4-NP). Curcumin nanoparticles were deposited on reduced graphene oxide nanosheets that were modified with nickel disulfide. The material was placed on a screen-printed carbon electrode and then displayed high electrocatalytic activities toward MP and 4-NP, with a peak potential near -0.9 and - 0.7 V (vs. pseudo Ag/AgCl), respectively. Figures of merit include (a) good electrochemical sensitivities (7.165 and 6.252 μA·μM·cm), (b) wide linear ranges (from 0.25 to 80 μM), (c) low limits of detection (8.7 and 6.9 nM at S/N = 3) for MP and 4-NP, respectively, and (d) good selectivity, repeatability, reproducibility, and storage stability. The method was applied in the determination of MP and 4-NP in tomato and apple juices and spiked river water. Graphical abstract A novel electrocatalysis platform based on reduced graphene oxide-nickel disulfide nanosheets decorated with curcumin nanoparticles for simultaneous quantification of methyl parathion and 4-nitrophenol in various vegetarian juices and water samples.