Magnetic solid-phase extraction using MIL-101 (Cr)-based composite combined with dispersive liquid-liquid microextraction based on solidification of a floating organic droplet for the determination of pyrethroids in environmental water and tea samples

An efficient magnetic metal-organic framework (MOF) material MIL-101(Cr)-based composite (MIL, Material Institute Lavoisier) was applied as a sorbent for magnetic solid phase extraction (MSPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method of trace pyrethroids in environmental water and tea samples. Target analytes were quantified by gas chromatography electron capture detection (GC-ECD). The variables influencing the performance of both steps, including amount of MIL-101 (Cr)-based composite, pH value, ultrasound extraction time, elution solvent, elution/disperser solvent volume, elution time and extraction solvent volume, were systematically investigated. The characteristics of the analytical method were evaluated. A linearity range (r = 0.9989-0.9997) was obtained in the range of 0.05-10.0 ng/mL. Excellent sensitivity levels were achieved with the detection limits of 0.008-0.015 ng/mL and the quantitation limits of 0.028-0.050 ng/mL. Under optimal conditions, the method was successfully established for the determination of pyrethroids in real samples with satisfactory recoveries ranging from 78.3-103.6%. Overall, the encouraging method exhibited the advantages of remarkable sensitivity, ease of operation, rapidity, low cost and environmental friendliness. (C) 2017 Elsevier B.V. All rights reserved.