Sustainable magnetic covalent organic framework materials for multi-residue analysis of pyrethroid pesticides in tobacco, fruits and vegetables

Abstract

Magnetic covalent organic frameworks (MCOFs) materials were synthesized in deep eutectic solvents (DESs) instead of traditional toxic organic solvents under ambient conditions. The reaction time could be reduced to about 3 h, which was more than 12 h for the traditional synthesis method. Materials characterization indicated that the MCOFs materials with Tp and BD as monomer synthesized in ChCl-urea based DESs (i.e. Urea-MTpBD) showed good magnetic property and higher specific surface area. The Urea-MTpBD materials were used as a magnetic solid phase extraction (MSPE) sorbent for the enrichment and determination of 16 pyrethroid pesticides (PYs), coupled with GC-MS/MS technology. The effective enrichment of PYs with Urea-MTpBD materials was achieved, which was due to the synergistic effects of π-π stacking and hydrophobic interactions. The limits of detection (LODs) of 16 PYs with the developed method ranged from 2.15 to 5.67 ng/mL, while the recovery was between 70.99 % and 109.09 % with excellent intra-day and inter-day precisions (RSDintra ≤ 5.78 %, RSDinter ≤ 9.13 %). The developed method was applied successfully to determine 16 PYs in tobacco, fruits and vegetables. Furthermore, the Urea-MTpBD materials could be reused three times, which showed not only highly efficient, but also economical and sustainable.