Cationic gemini surfactant templated magnetic cubic mesoporous silica and its application in the magnetic dispersive solid phase extraction of endocrine-disrupting compounds from the migrants of food contact materials

Fabrication of magnetic Fe3O4 doped β-cyclodextrin microporous organic network for the efficient extraction of endocrine disrupting chemicals from food takeaway boxes

Endocrine disrupting chemicals (EDCs) are a typical class of natural or man-made endogenous hormone agonists or antagonists that can directly or potentially interfere with human endocrine system. However, it is still difficult to analyze trace EDCs directly from complex environment and food matrices. Therefore, the proper sample pretreatment is highly desired and the preparation of efficient adsorbents is of great challenge and importance. Herein, we report the facile one-pot solvothermal synthesis of Fe3O4 nanoparticle doped magnetic β-cyclodextrin microporous organic network composites (MCD-MONs) for the magnetic solid phase extraction (MSPE) of four phenolic EDCs in water and food takeaway boxes prior to the high-performance liquid chromatography analysis. The sheet-like Fe3O4 doped MCD-MONs offered good magnetic property (16.5 emu g-1) and stability, and provided numerous hydrogen bonding, hydrophobic, π-π, and host-guest interaction sites for EDCs. Under the optimal experimental conditions, the established method was successfully verified with wide linear range (2.0-1000 µg L-1), low limits of detection (0.6-1.0 µg L-1), good precisions (intra-day and inter-day RSDs < 5.2 %, n = 3), large enrichment factors (88-98) and adsorption capacity (90.3-255.8 mg g-1), short extraction time (6 min), less adsorbent consumption (3 mg), and good reusability (at least 8 times) for EDCs. The proposed method was successfully applied to detect the trace EDCs in real samples with the recovery of 84.0-99.7 %. This work demonstrated the great potential of MCD-MONs for the efficient MSPE of trace EDCs from complex food takeaway boxes and water samples and uncovered the prospect of CD-based MONs in sample pretreatment.

Exploring a novel silicone surfactant-based deep eutectic solvent functionalized magnetic iron particles for the extraction of organophosphorus pesticides in vegetable samples

The current study discussed the use of silicone surfactant-based deep eutectic solvent as a surface modifier for magnetic iron particles (Fe₃O₄) to produce a novel adsorbent and its application for the extraction of organophosphorus pesticides (OPPs) in vegetable samples. A deep eutectic solvent (DES) was prepared using low toxic and inexpensive substances such as silicone surfactant (SS) and dodecanoic acid (DoAc). This new eco-friendly SS:DoAc based DES was explored as a substitution to traditional organic reagents for surface modification of Fe₃O₄ to increase the adsorption capacity and to reduce the matrix interferences, hazardous waste generation and environmental pollution. The newly synthesized SS:DoAc@Fe₃O₄ adsorbent was successfully characterized and applied in magnetic solid phase extraction (MSPE). Under optimized conditions, the proposed approach exhibited excellent linearity ranging from 0.1 to 200 µg/kg (R² ≥ 0.9970), low detection limit (0.03-0.1 µg/kg) and acceptable relative recovery (80-119 %) for the studied OPPs.

Recent advances of ordered mesoporous silica materials for solid-phase extraction

This review mainly focuses on the development and application of ordered mesoporous silica materials for solid-phase extraction in recent years. It overviews not only bare mesoporous silica but also the functionalized mesoporous silica with organic groups, molecularly imprinted polymers, and magnetic materials. These mesoporous silica materials were used as the extraction adsorbents in cartridge solid-phase extraction, dispersive solid-phase extraction, magnetic solid-phase extraction, micro-solid-phase extraction and matrix solid phase dispersion. Coupled with atomic emission spectrometry, chromatography or other detection methods, these techniques efficiently extracted and sensitively determined various targets, such as metal ions, perfluorocarboxylic acids, pesticides, drugs, endocrine disruptors, phenols, flavanones, polycyclic aromatic hydrocarbons, parabens and so on. Based on unique advantages of mesoporous silica materials, the developed analytical method successfully analyzed different matrix samples, like environmental water samples, soil samples, food samples, biological samples and cosmetics. In addition, the prospects of these materials in solid-phase extraction are presented, which can offer an outlook for the further development and applications.

Cationic Surfactant Modified 3D COF and Its Application in the Adsorption of UV Filters and Alkylphenols from Food Packaging Material Migrants

Hexadecyl trimethylammonium bromide (CTAB) micelles were applied in the synthesis of covalent organic frameworks (COFs) for the first time to achieve the synthesis of 3D COF from 2D materials. Benzidine, one raw material for COF, was enclosed in the CTAB micelles because of the hydrophobic effect, and thus the target COF, which can be formed immediately with the aid of p-toluenesulfonic acid, grew in a micelle guided 3D form. The synthesized 3D COF showed a flower-like structure, whereas the COF synthesized without CTAB showed a smooth structure. The diameter of the 3D COFs showed direct correlations with CTAB concentrations. Moreover, the CTAB modified COF also showed a dramatically improved fluorescence property in comparison with that of normal COFs. The synthesized 3D COF showed good adsorption performance for UV filters and alkylphenols with recoveries ranged from 90.2% to 99.8%, and it also showed good fluorescence response for Pb²⁺. The utility of CTAB modified COF was verified in the enrichment of UV filters and alkylphenols from food packaging material migrants.

Surfactant-modified Zn/Al-layered double hydroxides for efficient extraction of alkyl phenols from aqueous samples

Zn/Al-layered double hydroxides (LDHs) modified by sodium dodecylsulfate (SDS) were synthesized as a hydrophobic organic sorbent via urea hydrolysis. LDHs were applied as adsorbent for solid phase extraction (SPE) analysis to determine three alkylphenols (namely, p-tert-amylphenol (PTAP), p-cumylphenol (PCP), and p-n-octylphenol (POP)) in water samples using gas chromatography-mass spectrometry. The extraction efficiency was optimized by adjusting key variables of eluent volume, eluent type, sample flow rate, adsorbent amount, pH, and the effect of salt addition. Under the optimal conditions, APs showed excellent linearity (1-250 ng/mL: R² > 0.99) and reproducibility (relative standard deviation: <5%). The detection limits for PTAP, PCP, and POP were 19, 16, and 33 pg/mL, respectively. LDHs based SPE method offered high recovery for aqueous samples (e.g., 83.2-99.46%) with enhanced reusability (e.g., up to 10 cycles). The feasibility of the developed method has thus been validated for quantitation of three alkyl phenols (i.e., PTAP, PCP, and POP) in aqueous environmental samples with high sensitivity and good stability.