Graphene oxide doped polyamide nanocomposite coated on cellulose paper as a novel layered sorbent for microextraction by packed sorbent of organophosphorous pesticides

In this work, a novel layered sorbent for microextraction in packed syringe was introduced, which has been prepared by coating the solvent blend of graphene oxide/polyamide (GO/PA) nanocomposite 1, 2 (NC) onto cellulose paper through solvent exchange method. Scanning electron microscopy (SEM) was applied to investigate the surface characteristic and morphology of PA and GO/PA coated on cellulose paper. The prepared layered sorbent based on GO/PA nanocomposite was used for microextraction by packed sorbent (MEPS) 3-5 of organophosphorous pesticides (OPPs) including chlorpyrifos, fenthion, fenithrothion, ethion, edifenphos and phosalone in environmental aqueous samples followed by gas chromatography-flame ionization detector (GC-FID) detection. Important parameters affecting the MEPS processes including pH, extraction draw-eject cycles, sorbent layers, desorption solvent volume and desorption draw-eject number were studied and optimized using central composite design (CCD). Based on the method validation, limits of detection (LOD) were in the range of 0.2-1 ng mL-1.The method linear dynamic ranges were in 1- 500, 1-1000 and 3-1000 ng mL-1 for different analytes. The method precision (RSD %) with three replicates determinations were in the range of 2.1 to 11 % for distilled water at the concentration level of 300 ng mL−1. The developed method was applied successfully to determine OPP compounds in the river, dam and tap water samples; accordingly, the relative recoveries (RR%) were obtained in the range of 77.8 to 113.3%.