Magnetic Composite Based on Carbon Nanotubes and Deep Eutectic Solvents: Preparation and Its Application for the Determination of Pyrethroids in Tea Drinks

Abstract

In this study, a novel composite material prepared by using deep eutectic solvent (tetrabutylammonium chloride-dodecanol, DES₅) functionalized magnetic MWCNTs-ZIF-8 (MM/ZIF-8@DES₅) was employed as an adsorbent for the magnetic solid-phase extraction of six pyrethroids from tea drinks. The characterization results show that MM/ZIF-8@DES₅ possessed sufficient specific surface area and superparamagnetism, which could facilitate the rapid enrichment of pyrethroids from tea drink samples. The results of the optimization experiment indicated that DES₅, which comprised tetrabutylammonium chloride and 1-dodecanol, was selected for the next experiment and that the adsorption properties of MM/ZIF-8@DES₅ were higher than those of MM/ZIF-8 and M-MWCNTs. The validation results show that the method has a wide linear range (0.5-400 μg L^-1, R² ≥ 0.9905), low LOD (0.08-0.33 μg L^-1), and good precision (intra-day RSD ≤ 5.6%, inter-day RSD ≤ 8.6%). The method was successfully applied to the determination of pyrethroids in three tea drink samples.