Synthesis of magnetic amino-functionalized microporous organic network composites for magnetic solid phase extraction of endocrine disrupting chemicals from water, beverage bottle and juice samples

Abstract

In this work, the magnetic amino-functionalized microporous organic network composites (Fe₃O₄@MON-NH₂) were rational designed and facile synthesized for magnetic solid phase extraction (MSPE) of endocrine disrupting chemicals (EDCs), followed by their analysis with high-performance liquid chromatography. The incorporation of amino groups (hydrogen bonding sites) into hydrophobic MON-NH₂ networks led to their good enrichment for four typical EDCs bisphenol A (BPA), 4-alpha-cumylphenol (4-α-CP), 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP) relying on the pre-designed hydrogen bonding, π-π and hydrophobic interactions. The combination of MON-NH₂ shell and magnetic Fe₃O₄ core provided a fast extraction of BPA, 4-α-CP, 4-t-OP and 4-NP from matrix solution. Under the optimal conditions, the developed method offered good linearity (R² > 0.990) in the range of 0.05-1000 μg L^-1, low limits of detection (S/N = 3) of 0.015-0.030 μg L^-1 and large enrichment factors of 172-197 for the studied EDCs. The maximum adsorption capacities of BPA, 4-α-CP, 4-t-OP and 4-NP were 124.1, 105.6, 116.6 and 117.9 mg g^-1, respectively. The Fe₃O₄@MON-NH₂ gave larger selectivity for other polar phenols than non-polar polycyclic aromatic hydrocarbons, revealing the dominant role of hydrogen bonding interaction during the extraction and the potential of Fe₃O₄@MON-NH₂ for other polar phenols. The developed method was successfully applied for the analysis of EDCs in water, orange juice and beverage bottle samples with the recoveries of 80.3-109.5%. These results revealed the potential of functional MONs as efficient adsorbents in sample pretreatment.

Keywords: Composite; Endocrine disrupting chemicals; Magnetic solid phase extraction; Microporous organic network.