A surface imprinted polymer of type UiO-66-NH2@MIP was prepared by combining molecular imprinted polymers (MIPs) and an amino-functionalized zirconium-based metal-organic framework. Quercetin is used as the virtual template, UiO-66-NH 2 acts as the carrier to which the monomer acrylamide can be copolymerized. The material was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. It was used as a sorbent in a solid-phase extraction column. The extraction conditions were optimized. The adsorption capacities for aflatoxins AFB1, AFB2, AFG1 and AFG2 by this SPE and by the commercial SPE were compared. The method was successfully applied to quantify the aflatoxins in grain. Figures of merit include (a) good linearity (range from 0.20–45 μg·kg −1 ) with R 2 (range from 0.9986–0.9994), (b) low detection limits (90–130 ng·kg −1 ), (c) acceptable reproducibility (1.0–5.9%; for n = 6), and (d) relatively satisfactory recovery rates (74.3–98.6%). The new sorbent has good selectivity and reusability.
UiO-66-NH 2 @MIPs were synthesized with modified UIO-66-NH 2 as core and quercetin as pseudo template. A cartridge was prepared with the polymers as the sorbent, and its performance was compared with different commercial SPE cartridges.
Wenjing Liu,Guangjie Wu,Liping Wang,Jiaying Zhao,Renrong Liu
Immunoaffinity column (IAC) cleanup, coupled with high performance liquid chromatography (HPLC) analysis, is one of the most reliable methods for aflatoxin B1 (AFB1) analysis. However, real-time monitoring of the IAC capacity remains unachievable in IAC-HPLC analysis, compromising the reliability of AFB₁ quantification. Two artificial structural analogues of aflatoxin (AFB1-OH and AFB2-OH) were synthesized as potential markers for IAC capacity monitoring. Competitive ELISA and recovery experiments demonstrated that AFB2-OH was more suitable as a marker. When AFB2-OH was used for real-time monitoring of the capacity of the IAC in AFB1 determination by HPLC, the recovery of AFB1 exceeded 95 %. The limit of detection (LOD) and the limit of quantification (LOQ) for AFB1 were determined to be 0.14 ng/mL and 0.46 ng/mL, respectively. The method also exhibited good precision and accuracy. In spiked recovery experiments of four grains, the recovery of AFB1 ranged from 85.16 % to 107.05 % with relative standard deviations of 0.89 %-4.98 %. More importantly, due to the addition of AFB2-OH, the capacity of the IAC was monitored in real-time, ensuring the reliability of AFB1 determination results.
In the present study, for the first time, immunoaffinity columns under the term MIL (Al) −53 deep eutectic solvents @MIPs (MIL(Al)-53-DES@MIPs) were synthesized based on two technologies, metal–organic framework (MOF) and molecular imprinted polymers (MIPs). The MOFs and MIPs with DES used in synthesizing immunoaffinity columns, was subsequently used to extract and preconcentrate aflatoxins AFB1, AFB2, AFG1, and AFG2. One factor at a time (OFAT) method was used to optimize the parameters affecting on extraction efficiency of the target compounds. Under optimized conditions, the limits of detection of the four aflatoxin ranged from 0.023 to 0.033 µg kg −1 (S/N = 5), and the calibration graphs were linear in the concentration range from 0.1 to 400 μg kg −1 , the inter-day and intraday relative standard deviations (RSD) for various aflatoxins at three different concentration level (n = 5) using a single column were 1.3–4.4 %, and the column to column RSD % (n = 5) was 4.3–6.7 % at 5 μg L -1 of each analyte. The method was successfully applied to quantify aflatoxin in cereals samples of Khuzestan province of Iran, with the recoveries between 95.3 and 98.5 %.
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