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White pollution caused by the massive discharges of waste expanded polystyrene (WEPS) has become a critical global issue, so the effective conversion of WEPS is of great significance to reduce white pollution. Herein, adopting WEPS as raw material, three high-value-added hyper-crosslinked polymers (WEPS-HCPs) with high surface areas and abundant micro/mesoporous structures were synthesized via Friedel-Crafts alkylation reaction using dimethoxymethane, dichloroxylene and 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCB) as cross-linker, respectively. The WEPS-HCPs were used as sorbent to extract aflatoxins (AFs) and all the HCPs exhibited high adsorption capacity. For the fast separation and recovery of the sorbent, WEPS-BCB was chosen as a model HCP to be magnetically functionalized to obtain a magnetic HCP (mWEPS-BCB) for the first time. Based on magnetic solid phase extraction with the mWEPS-BCB as sorbent, a fast and sensitive method was developed to determine trace level of AFs in grain food. Under the optimal conditions, the proposed method presented wide linear range (0.008–10.0 ng g−1), low detection limit (0.002–0.015 ng g−1) and satisfactory precision (relative standard deviation < 7%). Converting WEPS into a high-value-added sorbent not only provided a facile strategy for effective recycling of WEPS, but also developed a sensitive method for accurate determination of AFs in grain food, achieving significant economic and environmental benefits. [ABSTRACT FROM AUTHOR]

• Magnetic POF was prepared using tetraphenylethylene as building unit. • The M-POF showed excellent adsorption capability for nitromidazoles. • A sensitive method was established for extracting nitromidazoles in chicken meat. • The M-POF can serve as a promising adsorbent for other adsorption applications. A magnetic porous organic framework (M-POF) was rationally designed and served as a sorbent for magnetic solid-phase extraction of six nitroimidazoles from chicken meat prior to their assay by high-performance liquid chromatography with diode array detection. The M-POF exhibited good magnetic responsiveness and outstanding affinity to nitroimidazoles with large adsorption capacity up to 36 mg g−1. Under optimal conditions, the developed method offered good linearity (r greater than 0.992) in the range of 1.5–100.0 ng g−1, low limits of detection (S/N = 3) of 0.5–0.8 ng g−1, low limits of quantification of 1.5–2.5 ng g−1 and high enrichment factors of 80–175 for the nitroimidazoles. The method was successfully applied to analyze nitroimidazoles in chicken meat. The recoveries were 80.2–118% with relative standard deviations lower than 12%. The adsorption mechanism was further explored and the results showed that the M-POF exhibited adsorption potential for compounds with strong polar interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, a novel magnetic hyper-crosslinked polymers (EA-MHCP1) was facilely synthesized by using biogenic ellagic acid (natural polyphenol) as monomer for the first time. The EA-MHCP-1 showed high extraction capacity toward neonicotinoid pesticides. Thus, it was applied as efficient sorbent to simultaneously extract four of the most frequently used neonicotinoids from environmental water and lettuces, followed by high performance liquid chromatography-diode array detection. This work provided a fast, reliable and sensitive tool for neonicotinoids detection. • A novel magnetic HCP (EA-MHCP) was facilely synthesized using biogenic ellagic acid. • EA-MHCP showed large adsorption capacity and fast adsorption rate to neonicotinoids. • H-bond and Lewis acid-base interaction may be the main adsorption mechanism. • EA-MHCP was applied as MSPE sorbent to detect neonicotinoids in water and lettuce. • EA-MHCP exhibited good application prospect for organic compounds with big polarity. 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. [ABSTRACT FROM AUTHOR]