Preparation of a magnetic phosphazene-based hyper crosslinked polymer for the fast and efficient extraction of chlorophenols from water and peach juice.

Two magnetic phosphazene-based hyper crosslinked polymers (M-HCP-OP-TMC and M-HCP-OP-TCL) were newly synthesized by the reaction of Friedel-Crafts acylation, and the M-HCP-OP-TMC showed an excellent extraction capability and rapid adsorption kinetics for chlorophenols as an adsorbent. Then, an efficient analytical method was built for the preconcentration and quantification of chlorophenols from water and peach juice samples by combining M-HCP-OP-TMC based magnetic solid-phase extraction (MSPE) with HPLC-UV detection. The linear response range for the chlorophenols by the method was 0.21-100.0 ng mL-1 for water sample, and 0.36-100.0 ng mL-1 for peach juice sample. The detection limits (S/N = 3) of the proposed method for the analytes were 0.07- 0.25 ng mL-1 and 0.12-0.45 ng mL-1 for water and peach juice samples, respectively. The method recoveries for the spiked samples were in the range of 93.1%-117.1%, and the relative standard deviations were less than 10%. The adsorption of the chlorophenols with the M-HCP-OP-TMC was mainly contributed by π-π stacking and hydrophobic interactions. The results indicate that the method was sensitive and accurate enough for the determination of the chlorophenols from real samples.

A core-shell structured magnetic sulfonated covalent organic framework for the extraction of benzoylureas insecticides from water, pear juice and honey samples.

Three magnetic covalent organic frameworks (named M-TpPa-SO3Na, M-TpPa-SO3H and M-TpPa) were prepared by the solvothermal synthesis method with 1,3,5-trimethylphenol (TP) and either 2-sulfo-1,4-phenylenediamine (Pa-SO3H) or p-phenylenediamine (Pa) as monomers. Among them, the M-TpPa-SO3Na possessed relatively high hydrophilicity, good magnetic responsiveness, and high affinity for the benzoylureas (BUs) insecticides. It was then explored as the magnetic solid-phase extraction adsorbent for the extraction of six BUs (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, flufenoxuron and chlorfluazuron) from water, pear juice and honey samples prior to high-performance liquid chromatography with ultraviolet detection. Under the optimized experimental conditions, a good linearity was achieved within the concentration range of 0.27-40.0 ng mL-1 for water sample, 0.47-30.0 ng mL-1 for pear juice sample, and 2.70-200.0 ng g-1 for honey sample. The limits of detection for the analytes were 0.08-0.11 ng mL-1 for water sample, 0.14-0.19 ng mL-1 for pear juice sample and 0.80-1.00 ng g-1 for honey sample. The method recoveries for spiked samples were in the range of 85.0%-111.0% with the relative standard deviations less than 8.8%. The developed method was successfully used for the determination of the BUs in water, pear juice and honey samples.