以牛血清白蛋白（BSA）为模板分子，多巴胺为功能单体，磁性四氧化三铁-石墨烯-多壁碳纳米管（Fe₃O₄-G/MWNT）为载体，制备了一种新型磁性分子印迹聚合物材料（Fe₃O₄-G/MWNT@MIP），用于萃取牛血清白蛋白。用10 mmol·L^-1的磷酸盐缓冲溶液（pH 6.0，含1.0 mmol·L^-1 NaCl）将血清样品稀释10倍，加入20.0 mg的Fe₃O₄-G/MWNT@MIP，振摇平衡20 min，弃去液体，用5.0 mL的10 mmol·L^-1 NaCl溶液（pH 6.0）洗涤固体，再用2.0 mL的0.5 mmol·L^-1 NaCl溶液（pH 5.0）解吸20 min，将洗脱液移至超滤管中，以12 000转·min^-1离心20 min后，取超滤液进行高效液相色谱分析。结果表明：Fe₃O₄-G/MWNT@MIP对BSA具有良好的选择性，最大吸附容量达56.79 mg·g^-1，重复使用20次后，最大吸附容量仅降低了7%。方法成功于应用于小牛血清中牛血清白蛋白的测定，加标回收率在90.0%~120%之间，测定值的相对标准偏差（n=7）小于3.0%。

A novel magnetic molecularly imprinted polymer (Fe₃O₄-G/MWNT@MIP) was prepared with bovine serum albumin (BSA) as the template molecule, dopamine as the functional monomer, and magnetic ferroferric oxide-graphene-multiwalled carbon nanotubes (Fe₃O₄-G/MWNT) as carriers, and used for extraction of BSA. After the serum sample was diluted 10-fold with 10 mmol·L^-1 phosphate buffer solution (pH 6.0, containing 1.0 mmol·L^-1 NaCl), 20.0 mg of Fe₃O₄-G/MWNT@MIP was added, and the mixture was shaken for 20 min. The liquid was discarded, and the solid was washed with 5.0 mL of 10 mmol·L^-1 NaCl solution (pH 6.0), then desorbed with 2.0 mL of 0.5 mmol·L^-1 NaCl solution (pH 5.0) for 20 min. The eluate was transferred into a ultrafitration tube and centrifuged at 12 000 r·min^-1 for 20 min, and the ultrafitrate was taken for high performance liquid chromatography analysis. The results showed that, Fe₃O₄-G/MWNT@MIP had good selectivity to BSA, and the maximum adsorption capacity was 56.79 mg·g^-1. After repeated use for 20 times, the maximum adsorption capacity only reduced by 7%. The method was successfully applied to determination of BSA in calf serum. Values of recovery obtained by standard addition method were between 90.0% and 120%, and the relative standard deviations (n=7) of the measured values were less than 3.0%.