Carboxyl-based deep eutectic solvent modified magnetic graphene oxide as a novel adsorbent for fast enrichment and extraction of estrogens in milk prior to HPLC-UV analysis

•A carboxyl-based deep eutectic solvent modified magnetic graphene oxide nanocomposite was synthesized via a facile strategy.•MGO@DES demonstrated excellent adsorption capability for hydrophobic estrogens.•The high reusability made MGO@DES valuable in practical application.•A fast and cost-effective MSPE-HPLC-UV method to quantify trace estrogens in milk was established.