3.1.2. FT-IR

The structures of the Bi-MIPs, Bi-NIPs, Si-MIPs and Si-NIPs were investigated by FT-IR spectroscopy, and the results are shown in Figure 3. As shown in Figure 3a, the Bi-MIPs, Bi-NIPs, Si-MIPs and Si-NIPs display a stretching vibration peak of -CH2- occurring at 2987 cm−1, indicating that MAA is contained in polymerization. The stretching vibration peak of the -NH- double bond appeared at 1456 cm−1, the single-bond vibration region of -CH appeared at 1398 cm−1, and the stretching vibration peak of -C=O occurred at 1732 cm−<sup>1</sup> [42–45]. The carbonyl groups tend to have a higher vibration absorption, indicating the successful preparation of the Bi-MIPs, Bi-NIPs, Si-MIPs and Si-NIPs. The partial single-bond vibration absorption peak of -COC- was observed at 1154 cm−<sup>1</sup> on the Bi-MIP curve, indicating the presence of EGDMA. At the same time, in the Bi-NIP, Si-MIP, and Si-NIP curves, partial single-bond vibration absorption peaks of -COC- were observed at about 1154 cm−1, indicating the presence of EGDMA, indicating that the polymer was successfully synthesized. The FT-IR of the Bi-MIPs and Bi-NIPs were almost the same. After removing the template molecule chrysin, the chemical structure and composition of the Bi-MIPs were the same as that of the Bi-NIPs. These results prove that the types of functional monomers have a certain influence on the synthesis of polymers, and the functional monomers play a role in the construction of adsorption pocket size.
