Tang Shuiping, Huang Yong, Zhao Shulin, Hu Kun
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources/Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004, PR China.
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources/Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin, 541004, PR China.
Talanta. 2023 Jun 1;258:124423. doi: 10.1016/j.talanta.2023.124423. Epub 2023 Mar 6.
Herein, a novel surface molecularly imprinted-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (SMI-MALDI-TOF MS) method for direct target paraquat (PQ) analysis in complicated samples is reported. Notably, a captured analyte-imprinted material can be directly detected via MALDI-TOF MS by using imprinted material as nanomatrix. Using this strategy, the molecular specific affinity performance of surface molecularly imprinted polymers (SMIPs) and the high-sensitivity detection capability of MALDI-TOF MS was integrated. The introduction of SMI endowed the nanomatrix with the capacity for rebinding the target analyte and ensuring specificity, prevented the interfering organic matrix, and enhanced the analyzing sensitivity. By using paraquat (PQ) as a template, dopamine as a monomer, and covalent organic frameworks with a carboxyl group (C-COFs) as a substrate, polydopamine (PDA) was decorated on C-COFs via a simple self-assembly procedure to generate an analyte-based surface molecularly imprinted polymer (C-COF@PDA-SMIP), which served the dual function of SMIP capturing the target analytes and high-efficiency ionization. Thus, a reliable MALDI-TOF MS detection PQ with high selectivity and sensitivity as well as an interference-free background was achieved. The synthesis and enrichment conditions of C-COF@PDA-SMIPs were optimized, and its structure and property were characterized. Under optimal experimental conditions, the proposed method achieved highly selective and ultrasensitive detection of PQ from 5 to 500 pg mL, and the limit of detection was as low as 0.8 pg mL, which is at least three orders of magnitude lower than that achieved without enrichment. In addition, the specificity of the proposed method was superior to that of C-COFs and nonimprinted polymers. Moreover, this method exhibited reproducibility, stability, and high salt tolerance. Lastly, the practical applicability of the method was successfully verified by analyzing complicated samples, such as grass and orange.
本文报道了一种基于新型表面分子印迹的基质辅助激光解吸/电离飞行时间质谱（SMI-MALDI-TOF MS）方法，用于直接分析复杂样品中的目标百草枯（PQ）。值得注意的是，通过将印迹材料用作纳米基质，可通过MALDI-TOF MS直接检测捕获的分析物印迹材料。利用该策略，整合了表面分子印迹聚合物（SMIP）的分子特异性亲和性能和MALDI-TOF MS的高灵敏度检测能力。SMI的引入赋予纳米基质重新结合目标分析物并确保特异性的能力，防止干扰有机基质，并提高分析灵敏度。以百草枯（PQ）为模板，多巴胺为单体，以含羧基的共价有机框架（C-COFs）为底物，通过简单的自组装程序将聚多巴胺（PDA）修饰在C-COFs上，生成基于分析物的表面分子印迹聚合物（C-COF@PDA-SMIP），其兼具捕获目标分析物的SMIP功能和高效电离功能。因此，实现了具有高选择性、高灵敏度且背景无干扰的可靠MALDI-TOF MS检测PQ。优化了C-COF@PDA-SMIPs的合成和富集条件，并对其结构和性能进行了表征。在最佳实验条件下，该方法实现了对5至500 pg mL的PQ进行高选择性和超灵敏检测，检测限低至0.8 pg mL，比未富集时至少低三个数量级。此外，该方法的特异性优于C-COFs和非印迹聚合物。而且，该方法具有重现性、稳定性和高耐盐性。最后，通过分析草和橙子等复杂样品，成功验证了该方法的实际适用性。
