共价有机骨架(COF)由于其可调的结构和功能而成为样品预处理的有吸引力的材料。然而,COF对复杂环境基质中污染物的精确识别仍然具有挑战性,因为它们的特定活性位点不足。在这里,我们报道了Co2配位辅助的分子印迹柔性COF(MI-COF@Co2)用于选择性识别曲霉毒素A(OTA)。MI-COF@Co2+是通过3,3-二羟基联苯胺的一步聚合制备的,2,4,6-三(4-甲酰基苯氧基)-1,3,5-三嗪,Co2+和模板。柔性单元赋予COF自适应调节分子构象并与Co2配位以定位印迹腔的能力。配位作用极大地提高了MI-COF@Co2+对OTA的吸附能力和选择性。将制备的MI-COF@Co2+作为固相萃取吸附剂用于OTA的高效液相色谱测定,检出限为0.03ngmL-1,相对标准偏差<2.5%。此外,该方法可以无干扰地测定实际样品中的OTA,回收率为89.5%至102.8%。这项工作提供了一种简单的方法来提高COF在复杂环境中测定危险化合物的选择性。
Covalent organic frameworks (COFs) are attractive materials for sample pretreatment due to their tunable structures and functions. However, the precise recognition of contaminant in complex environmental matrices by COFs remains challenging owing to their insufficient specific active sites. Herein, we report Co2+ coordination-assisted molecularly imprinted flexible COF (MI-COF@Co2+) for selective recognition of ochratoxin A (OTA). The MI-COF@Co2+ was prepared via one-step polymerization of 3,3-dihydroxybenzidine, 2,4,6-tris(4-formylphenoxy)- 1,3,5-triazine, Co2+ and template. The flexible units endowed COFs with the self-adaptable ability to regulate the molecular conformation and coordinate with Co2+ to locate the imprinted cavities. The coordination interaction greatly improved the adsorption capacity and selectivity of MI-COF@Co2+ for OTA. The prepared MI-COF@Co2+ was used as solid phase extraction adsorbent for high-performance liquid chromatography determination of OTA with the detection limit of 0.03 ng mL-1 and the relative standard deviation of < 2.5 %. In addition, this method permitted interference-free determination of OTA in real samples with recovery from 89.5 % to 102.8 %. This work provides a simple way to improve the selectivity of COFs for the determination of hazardous compounds in complex environments.