Johns Cameron, Shellie Robert A, Pohl Christopher A, Haddad Paul R
Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Private Bag 75, Hobart, Tasmania 7001, Australia.
J Chromatogr A. 2009 Oct 9;1216(41):6931-7. doi: 10.1016/j.chroma.2009.08.018. Epub 2009 Aug 13.
A two-dimensional ion chromatography (2D-IC) approach has been developed which provides greater resolution of complex samples than is possible currently using a single column. Two columns containing different stationary phases are connected via a tee-piece, which enables an additional eluent flow and independent control of eluent concentration on each column. The resultant mixed eluent flow at the tee-piece can be varied to produce a different eluent concentration on the second column. This allows analytes strongly retained on the first column to be separated rapidly on the second column, whilst maintaining a highly efficient, well resolved separation of analytes retained weakly on the first column. A group of 18 inorganic anions has been separated to demonstrate the utility of this approach and the proposed 2D-IC method provided separation of this mixture with resolution of all analytes greater than 1.3. Careful optimisation of the eluent profiles on both columns resulted in run times of less than 28 min, including re-equilibration. Separations were performed using isocratic or gradient elution on the first column, with an isocratic separation being used on the second column. Switching of the analytes onto the second column was performed using a gradient pulse of concentrated eluent to quickly elute strongly retained analytes from the first column onto the second column. The separations were highly repeatable (RSD of 0.01-0.12% for retention times and 0.08-2.9% for peak areas) and efficient (typically 8000-260,000 plates). Detection limits were 3-80 ppb.
已开发出一种二维离子色谱（2D - IC）方法，与目前使用单柱相比，该方法能对复杂样品提供更高的分辨率。两根装有不同固定相的色谱柱通过三通连接，这使得能够有额外的洗脱液流动，并能独立控制每根色谱柱上的洗脱液浓度。在三通处产生的混合洗脱液流可以变化，从而在第二根色谱柱上产生不同的洗脱液浓度。这使得在第一根色谱柱上强烈保留的分析物能在第二根色谱柱上快速分离，同时对在第一根色谱柱上弱保留的分析物保持高效、分离良好的状态。已分离出一组18种无机阴离子以证明该方法的实用性，所提出的二维离子色谱方法对该混合物的分离使得所有分析物的分辨率大于1.3。对两根色谱柱上的洗脱液曲线进行仔细优化后，运行时间不到28分钟，包括重新平衡。在第一根色谱柱上使用等度或梯度洗脱进行分离，在第二根色谱柱上使用等度分离。使用浓缩洗脱液的梯度脉冲将分析物切换到第二根色谱柱上，以便快速将在第一根色谱柱上强烈保留的分析物洗脱到第二根色谱柱上。分离具有高度可重复性（保留时间的相对标准偏差为0.01 - 0.12%，峰面积的相对标准偏差为0.08 - 2.9%）且效率高（通常为8000 - 260,000理论塔板数）。检测限为3 - 80 ppb。
