N-doped carbon dots derived from covalent organic frameworks embedded in molecularly imprinted polymers for optosensing of flonicamid

Abstract

After applied, flonicamid reaches the interior of agricultural products and shifts to ecosystem, which proliferating the hazardous risk to consumers. In this study, nitrogen-doped carbon dots derived from covalent organic frameworks embedded in molecularly imprinted polymers (COF-derived NCDs@MIPs) were prepared by reverse microemulsion polymerization. The COF-derived NCDs@MIPs were used as a potential candidate for the optosensing of flonicamid in food samples, which combined the merits of superior physicochemical properties with the high stability of N-doped carbon dots, an efficient fluorescence-resonance charge-transfer strategy, and good specific and sensitive MIP technology. The performance of the proposed optosensing system was measured in phosphate buffered saline (PBS, pH = 7.0) over the flonicamid concentration range of 0.03–0.3 μg g−1 with a limit of detection of 0.004 μg g−1. A selectivity study was employed to evaluate the influence of five neonicotinoids on the selectivity of the COF-derived NCDs@MIPs for flonicamid molecules, which showed good affinity for flonicamid in comparison with that of the non-imprinted polymer (NIP). The application of the proposed optosensing technique in spiked food samples revealed a good recovery (86.7–98.1%). The development of easily synthesized COF-derived NCDs@MIPs with excellent performance will be greatly beneficial for trace detection of flonicamid.