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研究了碱基在十二胺 N,N 二亚甲基膦酸(DDPA)改性氧化锆固定相(DPZ)上的色谱保留行为,考察了流动相中甲醇含量、流动相pH值、缓冲溶液中离子类型和离子强度对碱基保留的影响,对DDPA在氧化锆表面的吸附方式进行了研究。研究结果表明,DDPA仅以一个膦酸基与氧化锆结合,因而DPZ固定相表面上除了有长链的疏水烷基外,还有酸性的膦酸基和碱性的氨基。碱基分子中也存在氨基和酰胺基等极性基团,因此碱基在DPZ固定相上除了有疏水作用外,还具有电荷排斥作用、离子交换作用等多种保留机理。由于多种保留机理的存在,使得碱基在DPZ固定相上具有较好的分离选择性,在酸性条件下对碱基混合样品的分离取得了满意的结果。
The chromatographic retention behavior of the base on DPZ modified with dodecylamine N, N dimethyldiphosphonic acid (DDPA) was investigated. The effects of methanol content, mobile phase pH, buffer solution Ion type and ionic strength on the retention of the base, the adsorption of DDPA on the surface of zirconia was studied. The results show that DDPA binds zirconium oxide to only one phosphonate group. Therefore, the DPZ stationary phase has acidic phosphonic acid groups and basic amino groups in addition to long chain hydrophobic alkyl groups. Base molecules also have amino groups and amido groups and other polar groups, so the base in addition to hydrophobic DPZ stationary phase, but also has the charge repulsion, ion exchange and other retention mechanism. Due to the existence of a variety of retention mechanisms, the base has better separation selectivity on the DPZ stationary phase, and satisfactory results have been obtained for the separation of the base mixed sample under acidic conditions.