Imidazole-functionalized covalent organic framework for sensitive analysis of neonicotinoid insecticides

Developing an effective method for reliable monitoring of insecticide residues is desirable for public health. This study developed a rapid and sensitive method to determine neonicotinoid insecticides (NEONICs) in water, lemon beverage, wax gourd, and tomato samples. An imidazole-functionalized COF (TPT-DB-COF) featuring a spherical core-shell structure was developed and used as a solid-phase extraction (SPE) adsorbent. The TPT-DB-COF exhibited superior adsorption ability for NEONICs. The TPT-DB-COF-SPE/HPLC-DAD approach for trace analysis of NEONICs had low detection limits (0.02-0.03 ng mL^-1 for water samples, 0.07-0.08 ng mL^-1 for lemon beverage, 0.6-0.8 ng g^-1 for wax gourd samples, and 0.9-1.3 ng g^-1 for tomato samples), high trueness (method recoveries of 87.0% - 114%), and acceptable precision (relative standard deviations below 7.9%). Such good performance parameters pave the way for the application of TPT-DB-COF in the analysis of NEONICs.