A nanosilica/exfoliated graphene composite film-modified electrode for sensitive detection of methyl parathion

Graphene nanosheets(GS) were easily prepared through liquid-phase exfoliation of graphite powder in N,N-dimethylformamide(DMF) with the assistance of sodium citrate. Then, GS was coated onto a glassy carbon electrode(GCE) surface by drop to fabricate a GS/GCE nanointerface. Subsequently, by using tetraethylorthosilicate sol as precursor, nanosilica was electrochemically deposited onto the GS/GCE surface to produce a nanocomposite film electrode(nanosilica/GS/GCE). Electrochemical behaviors of methyl parathion(MP) on the nanosilica/GS/GCE surface were investigated thoroughly. It was found that the nanosilica/GS nanocomposites can improve the redox peak currents of MP significantly due to the synergetic effect. The oxidation peak current was linearly related to MP concentration in the range from0.0005 mmol/L to 5.6 mmol/L. The detection limit was calculated to be 0.07 nmol/L(S/N = 3). The developed method was used to determine MP in real samples. The recoveries were in the range from95.4% to 104.2%, demonstrating satisfactory results.