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In this work, an integrated sample‐pretreatment strategy for the separation and enrichment of microplastics and primary aromatic amines from the migration of teabag was developed. The migration solution of teabag was passed through a homemade device. The microplastics were firstly captured by a silver membrane, and then the primary aromatic amines were enriched by a solid‐phase extraction column. The microplastics migrated from teabag were detected by attenuated total reflection‐Fourier transform infrared spectrometer and Raman spectroscopy. The data showed the character, the number of particles, area ratio, and morphology of microplastics migrated from the teabag. Subsequently, after the enrichment procedure, a sensitive analytical method for primary aromatic amines was established followed by ultra‐high performance liquid chromatography‐tandem mass spectrometry. The method showed wide linear ranges with R2 greater than 0.9915, low limits of detection (2–18 ng/L), and low limits of quantification (8–50 ng/L). The developed method was adopted to analyze microplastics and primary aromatic amines migrated from nylon and polyethylene terephthalate teabag under different temperatures and times. The integrated sample‐pretreatment strategy displayed promising potentials in the one‐step preparation of the microplastics and hazardous molecules in the sample of environment and food security. [ABSTRACT FROM AUTHOR]

A novel metal-ion-mediated complex-imprinted-polymer-coated solid-phase microextraction (SPME) fiber used to specifically recognize thiabendazole (TBZ) in citrus and soil samples was developed. The complex-imprinted polymer was introduced as a novel SPME coating using a 'complex template' constructed with Cu(II) ions and TBZ. The recognition and enrichment properties of the coating in water were significantly improved based on the metal ion coordination interaction rather than relying on hydrogen bonding interactions that are commonly applied for the molecularly imprinting technique. Several parameters controlling the extraction performance of the complex-imprinted-polymer-coated fiber were investigated including extraction solvent, pH value, extraction time, metal ion species, etc. Furthermore, SPME coupled with HPLC was developed for detection of TBZ, and the methods resulted in good linearity in the range of 10.0-150.0 ng/mL with a detection limit of 2.4 ng/mL. The proposed method was applied to the analysis of TBZ in spiked soil, orange, and lemon with recoveries of 80.0-86.9% and RSDs of 2.0-8.1%. This research provides an example to prepare a desirable water-compatible and specifically selective SPME coating to extract target molecules from aqueous samples by introducing metal ions as the mediator. [ABSTRACT FROM AUTHOR]

Ractopamine, as an alternative beta-agonist to clenbuterol, is more and more used as leanness-enhancing agent in the swine industry. This work presents a new molecularly imprinted polymer (MIP) using ractopamine as template for dispersive solid-phase extraction of trace ractopamine and the structural related beta-agonists in animal tissues. The binding properties and selectivity of MIP were investigated. High selectivity in polar environment was found, since the extraction capacity of ractopamine with the MIP was 4.5-fold as much as that with the non-imprinted polymer in acetonitrile. Cross-selectivity investigation indicates that the MIP preferentially binds the template and then the structural analogues according to their molecular similarity. Thermodynamic and kinetic investigation was performed to interpret the specific adsorption and molecular recognition of the MIP for ractopamine. Standard free energy, standard enthalpy, and standard entropy were determined. Related information suggested that adsorption of ractopamine onto MIP was an exothermic, spontaneous process. The MIP can be applied as dispersive solid-phase extraction material for enrichment of ractopamine, isoxsuprine, fenoterol and clenbuterol in complex samples before HPLC analysis. The method revealed detection limits of 0.20-0.90 microg/L, recoveries of 83.8-115.2 and 85.2-110.2% for the spiked pig muscle and pig liver, respectively, with the RSD from 2.5 to 8.8%.