Luminescent Molecularly Imprinted Polymers Based on Covalent Organic Frameworks and Quantum Dots with Strong Optical Response to Quinoxaline-2-Carboxylicacid.

Zhang Zhang,Liu Liu

doi:10.3390/polym11040708

Abstract

Three-dimensional molecularly imprinted polymers (MIPs) based on quantum dots-grafted covalent organic frameworks (QDs-grafted COFs) are reported in this study. The compound 1,3,5-triformylphloroglucinol-P-phenylenediamine was used as COF material to react with the amino-modified CdSe/ZnS QDs by Schiff-base reactions. The amino-derived QDs reacted with quinoxaline-2-carboxylicacid (QCA) via a non-covalent interaction. The system combines the advantages of MIPs, COFs, and QDs for highly sensitive and selective QCA detection. The MIPs based on QDs-grafted COFs showed good chemical selectivity and thermal stability, as well as consistency in QCA optosensing. Under optimal conditions, the detection limit for QCA in meat and feed samples was 0.85 μmol L−1, over a linear concentration range of 1–50 μmol L−1. The current findings suggest a potential application of MIPs based on QDs-grafted COFs for the detection of trace levels of hazardous chemicals for food safety and environmental control.

Highlights

Luminescent covalent organic frameworks (COFs) with the porosity of COFs and intrinsic optical properties, which can transform the chemical signal produced by the host–guest interaction into detectable changes in luminescence, have attracted wide attention
quantum dots (QDs) were used as an optical response element, and COFs were used as an optosensing platform to combine the molecularly imprinted polymers (MIPs)
This study reports the clear advantage of MIPs coated on QDs-based COFs for simple and rapid optosensing of QCA

Summary

Introduction

Luminescent covalent organic frameworks (COFs) with the porosity of COFs and intrinsic optical properties, which can transform the chemical signal produced by the host–guest interaction into detectable changes in luminescence, have attracted wide attention. Dalapati et al have prepared a highly emissive COFs using an aggregation-induced emission-active chromophore to the π-frameworks It uses an aggregation-induced emission mechanism to interact with the intralayer covalent bonding, and the interlayer non-covalent π-interactions work to reduce rotation-induced thermal decay of the photo-excited state [10]. The highly luminescent COFs are first achieved, which use a high sensitivity sensor to reduce the detection limit of ammonia at the Polymers 2019, 11, 708; doi:10.3390/polym11040708 www.mdpi.com/journal/polymers. This framework laid the foundation for COFs application in the luminescent sensor field.

Methods

Results

Conclusion