中文摘要：

推导了芳香酸在动态磁涂覆混合纳米固定相开管毛细管柱中等度洗脱和二元台阶梯度洗脱条件下的输运方程，考察了其在该色谱柱上的保留特征．结果表明，等度洗脱时，电渗流方向及大小随着两种固定相配比的改变而改变，溶质的容量因子与弱阴离子交换固定相和反相固定相比例（Fe304@Si02．NH2：Fe3O4@SiO2-C18）之间具有良好的线性关系，拟合后相关系数大于0．9166．二元台阶梯度洗脱条件下，溶质的迁移时间可以通过其在等度洗脱条件下的洗脱时间加以预测．溶质在经磷酸缓冲液浓度、有机调节剂浓度和pH值台阶梯度洗脱后，其预测保留时间和实际保留时间之间的相对误差分别小于8．0％，10％和5．8％．构建的系统在优化的色谱条件下对水提天麻进行了分离，其主要成分柠檬酸的保留时间预测值与实际值之间相对误差为11％．

英文摘要：

In this paper, novel open-tubular electrochromatographic system with core/shell magnetic nanoparticles modified by amino and C18 functional groups as mixed stationary phase by using a series of permanent magnets to immobilize nanoparticles into the capillary were investigated. The new system showed high separation ability and efficiency due to high specific surface area of nanomaterial and mixing separation mechanism. The transport equations of aromatic acids using the open-tubular electrochromatographic column with magnetic nanoparticle coating as stationary phases were derived under isocratic and double stepwise gradient elutions, and the retention characteristics of organic acids separated by the columns were further investigated. The results showed that the electroosmotic flow gradually decreased with the increase of Fe304@SiO2-NH2 in the mixed stationary phases, and the direction of electroosmotic flow reversed eventually. The capacity factor was relevant to the ratio of ion-exchange and reversed-phase stationary phases. Furthermore, experiments confirmed that the capacity factor of solute had a good linear relationship with the ratio of mixed stationary phases, and the correlation coefficient was greater than 0.9166 after fitting. Under the double stepwise gradient elution condition, the migration time of solute can be predicted by its elution time under isocratic elution. After the solutes were eluted by phosphate buffer stepwise gradient elution, the relative errors between predicted retention time and actual retention time of solute were less than 8.0%. After they were eluted by organic modifier concentration stepwise gradient elution, the relative errors between two values of solute were less than 10%. After they were eluted by pH value stepwise gradient elution, the relative errors between two val- ues of solute were less than 5.8%. Rhizoma gastrodiae was separated by the constructed system under the optimized chroma- tographic condition, the main components of gastrodin, vanilla alcohol and citric aci