In situ hydrothermal growth of metal-organic gels coating for efficient solid-phase microextraction of pesticide residues

Abstract

In this study, a metal-organic gels (MOGs)-coated solid-phase microextraction (SPME) fiber was developed and coupled with gas chromatography-mass spectrometer (GC–MS) for highly sensitive detection of pesticide residues in fruit samples. The MOGs-coated fiber was prepared using a simple in situ hydrothermal growth method, and the influencing factors in preparation process were investigated in detail. The prepared fiber showed high extraction efficiency, and excellent acid and alkali resistance. Under the optimized conditions, the developed SPME-GC–MS method showed wide linearity in the range of 0.01–10.00 ng mL−1 for eleven pesticides. The limits of detection (LODs, S/N=3) and quantification (LOQs, S/N = 10) were in the range of 0.001–0.052 ng mL−1 and 0.005 -0.094 ng mL−1, respectively. The relative standard deviations (RSDs, n = 5) of single steel wire and steel wire to steel wire were all below 10.7%. The method was successfully applied to determine pesticide residues in fruit samples with satisfactory recovery of 79.3% -117.7% and RSDs varying from 2.9% to 9.6%. The MOGs-coated fiber stayed stable after 100 times extractions without significant changes in extraction capacity. The results indicated that the MOGs provided a promising coating for SPME of pesticide residues in complicated matrix.

Keywords

• Metal-organic gels
• Solid-phase microextraction
• Gas chromatography-mass spectrometry
• Pesticide residues
• Fruits