Graphene oxide/polydopamine-polyacrylamide nanocomposite as a sorbent for dispersive micro-solid phase extraction of diazinon from environmental and food samples and its determination by HPLC-UV detection

Graphene oxide/polydopamine-polyacrylamide nanocomposite as sorbent for dispersive micro-solid phase extraction of diazinon from environmental and food samples was synthesised and coupled with high-performance liquid chromatography-ultraviolet detector. The prepared sorbent was characterised by analytical techniques such as Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy-energy-dispersive spectroscopy and thermal gravimetric analysis. Main parameters affecting extraction efficiency of diazinon using dispersive micro-solid phase extraction such as sorbent amount, elution solvent and its volume, sorption and desorption times and pH of sample solution were investigated and optimised. The optimum values are as follow; sorbent amount, 0.2 g; elution solvent, methanol; elution solvent volume, 2.5 mL; sorption time, 10 min; desorption time, 4 min and pH of sample solution, 3. Under the optimised conditions, method detection limit and limit of quantitation values were 0.24 and 1.0 ng/mL, respectively. Relative recovery data for several real samples were obtained within the range of 82.0-98.0% with a relative standard deviation less than 6.5%. The proposed method was successfully applied to quantitative determination of diazinon in several environmental and food samples.