urface-initiated atom transfer radical polymerization（SI-ATRP） technique is an attractive polymer grafting,in which the polymer chains with controlled molecular weight and molecular weight distribution can be obtained.The graft density is controlled by the surfaces density of the initiator,and the graft chain length by the ratio of monomer to initiator or the polymerization time.It plays an important role in the preparation of functional materials in the field of separation science.In this paper,SI-ATRP of dimethylaminoethyl methacrylate（DMAEMA） was conducted on the surface of 5 μm silica using 2-bromoisobutyryl bromide as the initiator and CuBr/1,1,4,7,7-pentamethyldiethylenetriamine（PMDETA） as the catalytic system,a novel PDMAEMA chromatographic stationary phase was obtained in DMF medium at 60 ℃.The three stationary phases with different chain lengths of the grafted DMAEMA were tried by manipulating the polymeric conditions.The concentrations of DMAEMA were changed but the polymerization time kept the same for three DMAEMA-grafted silica.For the first one named as ATRP1,[DMAEMA]/ [initiator]/[CuBr]/[PMDETA] ratios were selected as 50∶2∶1∶2,the second（ATRP2）,[DMAEMA]/[initiator]/[CuBr]/ [PMDETA] ratios as 75∶2∶1∶2,and the third（ATRP3）,[DMAEMA]/[initiator]/[CuBr]/[PMDETA] ratios as 100∶2∶1∶2.Three stationary phases were characterized by means of elementary analysis.The synthesized stationary phases were evaluated in detail to determine its separability,effect of the content of water and the salt concentration in the mobile phase on the retention of solutes.The stationary phases can effectively separate seven nucleosides in HILIC mode,and the retention time of nucleosides have a positive relationship with increasing the chain lengths of the grafted poly（DMAEMA）.It was used for separation and determination of some nucleoside compounds in Ningxinbao Capsule.Compared with NH2hydrophilic interaction chromatographic column for separation of these compounds under the same chromatographic conditions,the separation efficiency is better.The results showed that the retention of solutes was controlled by partitioning between mobile phase and a water-rich layer immobilized on the stationary phase.The stationary phase has good chromatographic properties for separation of polar compounds.%以甲基丙烯酸二甲氨乙酯为单体,2-溴异丁酰溴为引发剂,CuBr/五甲基二乙烯基三胺（PMDETA）为催化剂,通过原子转移自由基聚合（ATRP）反应,将甲基丙烯酸二甲氨乙酯（DMAEMA）接枝到5μm大孔硅胶表面上,得到了接枝聚合物（PDMAEMA）亲水作用色谱固定相.通过改变反应体系中单体的量,制备了三种不同接枝量的亲水作用色谱固定相,利用元素分析对所制备的固定相进行了表征.详细考察了该固定相的分离性能以及流动相中盐浓度、水含量对溶质保留行为的影响,并将该固定相用于宁心宝胶囊中核苷类化合物的分离和测定.在亲水模式下,该固定相可以基线分离7种核苷类化合物,保留时间随着接枝量的增加而增大,与氨基亲水作用色谱柱相比,该合成柱的分离效率高,溶质在该填料上的保留符合分配作用保留机理.实验结果表明,该填料具有良好的分离性能.
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