酸性化合物在十二胺-N,N-二亚甲基膦酸改性氧化锆固定相上的分离  

Separation of Acidic Compounds on Dodecylamine-N,N-Dimethylenephosphonic Acid Modified Zirconia Stationary Phase

作　　者：姚礼峰[1,2] 靳素荣[3] 冯钰锜[1] 达世禄[1] 

机构地区：[1]武汉大学化学与分子科学学院,武汉430072 [2]武汉理工大学理学院武汉 [3]武汉理工大学理学院

出　　处：《应用化学》2005年第6期605-609,共5页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金资助项目(20275029)

摘　　要：用十二胺N,N二亚甲基膦酸(DDPA)改性氧化锆制备了一种新的色谱固定相(DPZ)。比较了改性方法对吸附量的影响,加热回流时DDPA吸附量为3.3μmol/m2,而浸渍改性时只有0.64μmol/m2。通过磷的显色反应发现,DDPA只以1个膦酸基团与氧化锆结合,而另一个膦酸基团则处于游离状态。通过甲醇含量、pH值等色谱条件对酸性化合物保留值的影响,对保留机理进行了探讨,由于回流改性得到的固定相具有较高的吸附量,且游离的膦酸基团对基质表面的Lewis酸性中心具有较强的屏蔽作用,因此酚、羧酸等与氧化锆基质的Lewis酸碱作用明显减小。在该固定相上,酸性化合物的色谱性能得到明显改善,硝基酚、苯二酚等在氧化锆上通常难以洗脱的酚类化合物,均得到了高效分离。A new zirconia-based stationary phase(DPZ) was prepared from zirconia modified with dodecyla- mine-N,N-dimethylenephosphonic acid(DDPA). The surface coverage of DDPA was 3.3 μmol/m 2 when DPZ was modified under reflux, and only 0.64 μmol/m 2 when DPZ was just impregnated in a DDPA solution( without refluxing). The results of color reaction of zirconia with ammonium molybdate indicate that, in both cases, DDPA adsorbed on zirconia via the combination of one phosphonic group with zirconia, and another phosphonic group was free. The mechanism was studied in detail based on the influence of methanol content and pH of mobile phase on the capacity factors of the acidic compounds. The free phosphonic groups shielded most of the Lewis-acid sites on the surface of zirconia and imparted negative charges on the surface at high pH, resulting in excellent resolution for phenols and a great improvement for the separation of benzoic acids.

关 键 词：氧化锆 色谱固定相 十二胺-N N-二亚甲基膦酸 

分 类 号：O658[理学—分析化学]