Solid phase microextraction of phthalic acid esters from vegetable oils using iron (III)-based metal-organic framework/graphene oxide coating

A hybrid composite featuring an iron-based metal-organic framework Material of Institute Lavoisier-88(Fe) and graphene oxide (MIL-88(Fe)/GO) was synthesized and used as the solid-phase microextraction (SPME) coating. The SPME fiber was prepared by covalent bonding of the MIL-88(Fe)/GO composite onto the stainless steel substrate. The fiber had a good durability and allowed > 100 replicate extractions. The developed method, which combined the (MIL-88(Fe)/GO coated fiber based SPME with gas chromatography-flame ionization detection (GC-FID), achieved low limits of detection (0.5-2.0 ng g(-1), S/N=3) and good linearity (r(2) > 0.994) for the phthalic acid esters (PAEs) from various vegetable oil samples. The repeatability and fiber-to-fiber reproducibility were in the range of 4.0-9.1% and 5.7-11.4%, respectively. The method was successfully applied to the analysis of PAEs from vegetable oil samples with good recoveries (83.1-104.1%) and satisfactory precisions (RSDs < 10.5%), indicating that the MIL-88(Fe)/GO hybrid composite is a good coating material for the SPME of PAEs.