Selective enrichment and determination of polychlorinated biphenyls in milk by solid-phase microextraction using...

Owing to the severe toxicity and health hazard of polychlorinated biphenyls (PCBs) to humans, the efficient separation and determination of PCBs in dairy products is highly desirable and challenging. In this study, a new solid-phase microextraction (SPME) fiber was prepared by coating of a new molecularly imprinted phenolic resin (MIPR) in situ using a covalent grafting method. The MIPR coating, synthesized from 4-mercaptophenol and glutaraldehyde, provides rough surface with more adsorption sites; furthermore, the coating has a thickness of 1.0 μm, resulting in rapid equilibration. This new device has the advantages such as less coating peeling from the substrate and selective recognition enhancement of the coating. A highly selective and sensitive SPME-based method was developed using the developed fiber, coupled with GC-MS/MS, for the determination of polychlorinated biphenyls (PCBs) in milk samples. The developed MIPR-HS-SPME-GC-MS/MS method showed low detection limits (0.012-0.066 pg mL^-1), good linearity (r ≥ 0.9991), satisfactory recovery (77.5-116.7%), efficient enhancement factors (362-2034 folds) and good reusability (50 cycles). Therefore, this is a simple and efficient strategy for monitoring trace PCBs in complex samples and is a potential alternative for improving the selectivity of SPME fibers by introducing MIPR into the fiber coating.