Gritti Fabrice, Guiochon Georges
Department of Chemistry, University of Tennessee, Knoxville, TN 37996-1600, USA.
J Chromatogr A. 2009 Apr 10;1216(15):3175-84. doi: 10.1016/j.chroma.2009.02.013. Epub 2009 Feb 11.
Overloaded band profiles of aniline (25 microL injection of a 30.5mM solution) eluted with a methanol-aqueous buffer solution (30/70, v/v) were recorded at the exit of a 150 mm x 4.6mm column packed with 3.5 microm XBridge-C(18)porous particles. The SWpHs of the mobile phase was adjusted with phosphate (SWpHs approximately 2.7 and SWpHs approximately 7.5) or acetate buffers (SWpHs approximately 5.3) of different concentrations (11, 56, and 278 mM). The elution times and profiles of the bands observed at low ionic strength were successfully accounted for using the extended Debye-Hückel theory to estimate the activity coefficients of the ions in the bulk phase and a simple non-competitive Langmuir adsorption model, the adsorption of pure aniline or pure anilinium onto XBridge-C(18) being described by a Langmuir isotherm. The band profiles were calculated using this adsorption model and the equilibrium-dispersive model of chromatography. The calculated and the experimental band profiles are in excellent agreement at all buffer pH and ionic strength. This demonstrates that the elution times and the band profiles are controlled by the chromatographic dilution process and by the reaction of aniline with the buffer solution.
在一根填充有3.5微米XBridge-C(18)多孔颗粒的150毫米×4.6毫米色谱柱出口处，记录了用甲醇 - 水缓冲溶液(30/70, v/v)洗脱的苯胺(注入25微升30.5毫摩尔溶液)的过载谱带图谱。流动相的SWpHs用不同浓度(11、56和278毫摩尔)的磷酸盐(约2.7和约7.5)或乙酸盐缓冲液(约5.3)进行调节。利用扩展的德拜 - 休克尔理论估计本体相中离子的活度系数，并结合一个简单的非竞争性朗缪尔吸附模型，成功解释了在低离子强度下观察到的谱带洗脱时间和图谱，其中纯苯胺或纯苯胺鎓在XBridge-C(18)上的吸附由朗缪尔等温线描述。使用该吸附模型和色谱的平衡 - 分散模型计算谱带图谱。在所有缓冲液pH值和离子强度下，计算得到的谱带图谱与实验谱带图谱都非常吻合。这表明洗脱时间和谱带图谱受色谱稀释过程以及苯胺与缓冲溶液反应的控制。
