Yan Zhang,Donghao Liu,Jun Peng,Yanru Cui,Yi Shi,Hua He
A novel magnetic surface molecular imprinted polymers with 2, 4, 6-trisacrylamido-3, 5-triazine (TAT) as a functional monomer was successfully synthesized and used for the enrichment and determination of zearalenone . The molecular imprinting is reported herein at first time for application of zearalenone in wheat. The magnetic imprinted materials possessed excellent magnetism and uniform appearance, which were characterized by fourier transform infared spectroscopy and transmission electron microscope. The results proved the magnetic molecular imprinted polymers was successfully prepared. The magnetic molecular imprinted polymers exhibited satisfactory sensitivity, stability and potential reusability. The binding affinity was investigated by selectivity experiment, which possessed high selectivity. To obtain the optimal application conditions, the amount of adsorption, extraction time, elution solvent and time were optimized. The limited detection of zearalenone was 0.55 ng g −1 and the recoveries of zearalenone were 92.1–96.0%. The relative standard deviation was lower than 5.4%. This indicated that a simple, efficient and low-cost method was established and successfully applied in spiked wheat sample.
The monodispersed mesoporous SiO 2 @metal-organic framework (MSN@MIL-101(Fe)) composites were prepared by grafting MSN-NH 2 onto MIL-101(Fe) particles with a solvothermal method. The adsorption ability of the composites was greatly improved compared to that of pristine MSNs or MIL-101(Fe) for phytohormones (Phys). The MSN@MIL-101(Fe) composites were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, energy dispersive spectrometer, and mapping analysis. Using MSN@MIL-101(Fe) composites as sorbent, a dispersive solid-phase extraction procedure (dSPE) was developed to extract three endogenous Phys (abscisic acid (ABA), indole-3-aceticacid (IAA), and indole-3-butyric acid (IBA)) and two exogenous Phys (1-naphthylacetic acid (1-NAA) and 2-naphthylacetic acid (2-NAA)) prior to HPLC-DAD analysis. The experimental parameters including sample volume, sorbent amount, adsorption time, adsorption pH, desorption time, and desorption solvent on extraction efficiency were optimized and evaluated. Under optimized conditions, the working range of 0.08 to 0.45 ng mL −1 with enrichment factors from 144 to 207 were achieved. The linear range is 0.75–200 ng mL −1 for IAA, 0.20–200 ng mL −1 for ABA, and 1.0–200 ng mL −1 for IBA, 1-NAA, and 2-NAA. With MSN@MIL-101(Fe) as sorbent for extraction of Phys and determination by HPLC-DAD, two endogenous Phys (IAA and ABA) were detected from mung bean sprouts which were made in a laboratory, and the results were further confirmed by high-resolution mass spectrometry. The composites can be applied to extract other small molecules, which have similar chemical structures with Phys in biological, environmental, and food samples.
Schematic presentation of a dispersive solid-phase extraction using monodispersed mesoporous SiO 2 @metal-organic framework composites (MSNs@MIL-101(Fe)) as the sorbent for extraction, clean-up, and preconcentration of phytohormones in mung bean sprouts prior to HPLC-DAD analysis.