Magnetic frame work composite as an efficient sorbent for magnetic solid-phase extraction of plasticizer compounds

Two metal-organic frameworks (MOFs) TMU-23 and TMU-24, containing amide-functionalized pores, have been fabricated. Their applications were evaluated for the magnetic solid phase extraction of plasticizer compounds benzylbutylphthalate (BBP), di-2-(ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) prior to analysis by gas chromatography with flame ionization detector (GC-FID). Due to the large surface area and unique porous structure of the MOFs as well as hydrogen bonding formation, π-π and hydrophobic interactions between the analytes and the MOF ligands, the prepared sorbents showed a high affinity towards the target analytes. The studies reveal that TMU-24 has a better adsorption capability than TMU-23. A magnetic TMU-24 was then fabricated by in-situ synthesis of a magnetic core-shell nanocomposite. The material was chosen as an efficient sorbent for the extraction of the target analytes, followed by their determination by GC-FID. Under optimal conditions, preconcentration factors and relative recoveries of the studied compounds were obtained in the range of 189-278 and 92.0-102.0% respectively. The calibration curves were obtained in the range of 0.5-250 μg L−1 with reasonable linearity (R2 >0.99) and the limits of detection (LODs) ranged between 0.2 and 0.4 μg L−1 (based on S/N = 3). The precision of the method, expressed as relative standard deviation for extraction and determination of the 100 μg L−1 analytes in the samples solution was in the range of 3.9-5.9%.