Magnetic Solid-Phase Extraction of N,N-Diethyl-m-Toluamide From Baby Toilet Water Prior to its HPLC–UV Detection

Fe3O4@MIL-100 (MIL, Material Institut Lavoisier) core–shell magnetic microspheres were prepared and applied as the sorbent for the magnetic solid phase extraction (MSPE) of N,N-diethyl-m-toluamide (DEET) in baby toilet water for the first time. The synthesized magnetic metal–organic frameworks were characterized by transmission electron microscope, infrared spectroscopy and thermogravimetric analysis. The functionalized magnetic microparticles showed excellent dispersibility in aqueous solution. The MSPE conditions were investigated in detail. Under the optimized conditions, an MSPE–high performance liquid chromatography method for the determination of DEET was developed. The method was linear in the concentration range from 5 to 500 μg L−1 for DEET in baby toilet water and good linearity (r2 > 0.9998) was obtained for the calibration curve. The limit of detection was 1.5 μg L−1. Both the intra-day and inter-day precisions (relative standard deviations) were <3%.