Electro-deposited poly-luminol molecularly imprinted polymer coating on carboxyl graphene for stir bar sorptive extraction of estrogens in milk

•CG was used as supporter of MIP to increase adsorption capacity.•MIP coating was simply fabricated based on electro-polymerization luminol.•MIP/CG SBSE coupled with HPLC was applied to determinate three estrogens in milk.

Electrochemical polymerization of luminol molecularly imprinted polymer on carboxyl graphene (MIP/CG) was developed as stir bar sorptive extraction (SBSE) coating for selective pre-concentration and specific recognition of bisphenol A (BPA), hexoestrol and diethylstilbestrol in milk samples. Luminol was employed as monomer and BPA as the template to prepare MIP under 0–0.6 V electro-polymerization. Carboxyl graphene was modified on pencil lead as the substrate to increase extraction capacity. The preparation and extraction conditions affecting the extraction efficiency were optimized. Under the optimized conditions, a good linearity of three estrogens was obtained in the range of 4–1000 ng mL−1. The average recoveries at the three spiked levels of the three estrogens ranged from 83.4% to 96.3% with the relative standard deviations (RSD) ≤ 7.1%. The limits of detection were in the range of 0.36–1.09 ng mL−1. The developed method with low cost, high selectivity and good reproducibility can be potentially applied for determining trace estrogens in complex food samples.