Preparation of magnetite/poly(styrene-divinylbenzene) nanoparticles for selective enrichment-determination of fenitrothion in environmental and biological samples

► A magnetic nano-sized cross-linked polystyrene was used as an efficient adsorbent. ► The adsorbent was precipitated in the presence of naked magnetite nanoparticles. ► Fenitrothion was determined after extraction by the prepared adsorbent. ► One milliliter of 1-propanol efficiently eluted the formed colored product.