Preparation of boric acid functionalized hyper-crosslinked polymer for efficient extraction of phenylurea herbicides from lake water, green tea drink and tomato samples

A boric acid functionalized hyper-crosslinked polymer (HCP), designated as NPCBA/TBM-HCP, was successfully synthesized via Friedel-Crafts reaction by copolymerizing N-phenylcarbazole-2-boronic acid (NPCBA) and 2,4,6Tris(bromomethyl)mesitylene (TBM). The NPCBA/TBM-HCP showed a large surface area and a good adsorption property for phenylurea herbicides (PUHs). A method with NPCBA/TBM-HCP based solid phase extraction and high-performance liquid chromatographic detection was developed for the simultaneous analysis of PUHs in lake water, green tea drink and tomato samples. Under the optimized experimental conditions that the amount of the NPCBA/TBM-HCP was 30 mg, sample solution was 100 mL, sample loading rate was 4 mL min-1, and eluent was 0.3 mL acetonitrile, the linear response for the PUHs was in the range of 0.06-80.0 ng mL-1, 0.6-80.0 ng mL-1 and 0.9-200 ng g-1 for lake water, green tea drink and tomato samples, respectively, with a good linearity (the coefficients of determination (r2) >= 0.9916). The detection limits (S/N = 3) for lake water, green tea drink and tomato samples were 0.02-0.03 ng mL-1, 0.2 ng mL-1 and 0.3-0.5 ng g-1, respectively. The method recoveries for spiked samples were 80.0 %-119.1 % and RSDs were lower than 9.9 % for the determination. The method provides a new and feasible approach for the determination of phenylurea herbicide in real samples.