Direct synthesis of graphene–chitosan composite and its application as an enzymeless methyl parathion sensor

This paper proposed a direct electrodeposition approach to synthesis of graphene–chitosan (GR–CS) composite onto glassy carbon electrode (GCE) under controlled potential. This direct electrodeposition approach for the construction of GR-based hybrid was environmentally friendly, which would not involve the chemical reduction of graphene oxide (GO) and therefore result in no further contamination. The whole procedure was simply and cost only several minutes. Moreover, Combining the advantages of GR (large surface-to-volume ratio and high conductivity) and CS (good biocompatibility and adsorption), the GR–CS composite could be highly efficient to capture OPs and used as solid phase extraction (SPE). The GR–CS/GCE was used to detect organophosphate pesticides (OPs), using methyl parathion (MP) as a model analyte. The significantly redox response of MP on the GR–CS/GCE was proved. The linear range was wide from 4.0 ng mL−1 to 400 ng mL−1, and a low detection limit of 0.8 ng mL−1 for MP was achieved. Moreover, the proposed sensor exhibited high reproducibility, long-time storage stability and satisfactory anti-interference ability. The proposed GR–CS/GCE opens new opportunity for green, fast, simple, and sensitive analysis of OP compounds.