Synthesis of hydroxyl-functional magnetic hypercrosslinked polymer as high efficiency adsorbent for sensitively detecting neonicotinoid residues in water and lettuce samples

Three hydroxyl-functionalized magnetic hyper-crosslinked polymers (EA-MHCPs) were facilely synthesized using biogenic ellagic acid (EA) as monomer for the first time. The EA-MHCP1 possessed large surface area, good magnetism and excellent extraction capability toward neonicotinoids. Thus, an EA-MHCP1 based magnetic solid phase extraction method coupled with HPLC was developed for simultaneous analysis of four neonicotinoids in water and lettuce samples. At optimized conditions, excellent linear response (R2 >= 0.9990) was observed in the range of 0.06-100 ng mL-1 for water and 2.5-250 ng g- 1 for lettuce. Low detection limits (S/N = 3) were obtained over the range of 0.02-0.03 ng mL-1 for environmental water and 0.8-3.2 ng g- 1 for lettuce samples. Good method recoveries ranging from 80.0 % to 116 % were obtained, with relative standard deviations below 7.1 %. This work provided a robust analysis method for sensitively determining neonicotinoid residues in real samples.