Preparation and application of a restricted access material with hybrid poly(glycerol mono-methacrylate) and cross-linked bovine serum albumin as hydrophilic out layers for directly on-line high performance liquid chromatography analysis of enrofloxacin and gatifloxacin in milk samples

•A hybrid pGMMA and cross-linked BSA as hydrophilic layers for RAM was synthesized.•In column cross-linking adsorbed BSA was employed in the preparation.•The RAM column has good protein exclusion efficiency and long term stability.•The RAM column was employed as a SPE column in online SPE/HPLC.•Enrofloxacin and gatifloxacin in milk were analyzed by direct injection.