Preparation of a magnetic graphene/polydopamine nanocomposite for magnetic dispersive solid-phase extraction of benzoylurea insecticides in environmental water samples

A magnetic graphene/polydopamine (MG/PDA) nanocomposite has been prepared and used as sorbent for magnetic dispersive solid-phase extraction (MDSPE) of four benzoylurea insecticides in environmental water samples. The obtained nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, powder X-ray diffraction, fourier transform infrared spectroscopy, surface area and porosity analysis and thermogravimetric analysis. To investigate the adsorption performance of MG/PDA for target analytes, various parameters affecting the MG/PDA-based MDSPE procedure were optimized. Under the optimal conditions, the established method exhibits good linearity (R-2 >= 0.9988) in the concentration range 2.5-500 mu g L-1. A low limit of detection (0.75 mu g L-1, signal/noise = 3:1), a low limit of quantification (2.50 mu g L-1, signal/noise =10:1), and good precision (intraday relative standard deviation <= 3.6%, interday relative standard deviation <4.5%) are also achieved. Finally, the simple, fast, and sensitive sample preparation technique was successfully used to determine benzoylurea insecticides in environmental water samples.