Application of bio-metal-organic framework-based magnetic dispersive solid phase extraction for the extraction of polycyclic aromatic hydrocarbons from pasteurized milk

Abstract

This work describes the development of a magnetic dispersive solid phase extraction method based on using bio–metal–organic framework (prepared from vitamin B3 and cobalt salt in water medium) as an efficient sorbent for the extraction of polycyclic aromatic hydrocarbons from milk samples. Briefly, the synthesized sorbent at mg–level is added to the supernatant phase after precipitating the proteins of milk sample and the mixture is vortexed. In the presence of magnetic field, the supernatant is removed and the sorbent particles containing the adsorbed analytes are eluted by using an appropriate organic solvent. The eluted analytes are more enriched using a magnetic ionic liquid–based dispersive liquid–liquid microextraction. After back–extraction of the analytes into n–hexane, the analytes are determined using gas chromatography–mass spectrometry. The experimental variables influencing the suggested method efficiency such as zinc sulfate solution concentration and volume, and vortexing time in proteins precipitating step, sorbent amount, adsorption time, ionic strength, elution solvent type and volume, desorption time, extraction solvent type and volume, and back–extraction solvent type, volume and time in extraction procedure were optimized by one parameter at a time strategy. Under the optimum conditions, low limits of detection (38–78 ng L−1) and quantification (130–260 ng L−1), high extraction recoveries (58–82%) and enrichment factors (145–205), and good precision (relative standard deviations ≤6.1%) were obtained. Finally, the developed method was effectively employed for quantification of polycyclic aromatic hydrocarbons in pasteurized milk samples.