Restricted access magnetic core-mesoporous shell microspheres with C8-modified interior pore-walls for the determination of diazepam in rat plasma by LC-MS

► An enrichment technique based on C8-Fe3O4@mSiO2 microspheres was developed. ► Mesopores on the surface of the microspheres exclude proteins from the sample. ► The C8 groups modified on the inner walls extract drug molecules from the sample. ► The strong magnetic behavior of the microspheres ensure a fast and easy separation.