单柱离子色谱法测定一价阳离子的流动相研究

Study on the Mobile Phase for Determining Monovalent Cations by Single Column Ion Chromatography

对单柱离子色谱法测定一价阳离子的流动相进行了系统研究，阐述了一价阳离子的保留行为和电导检测行为与流动相之间的关系，分别对无机酸（硝酸）、有机酸（柠檬酸）和芳香碱（苯胺）为流动相测定一价阳离子进行了讨论，其中有机酸和无机酸是较为适宜的流动相。

A systematic study on mobile phase for determination of monovalent cations by single column ion chromatography is described. An equation to describe the retention behaviour of monovalent cations in single column ion chromatography has been developed. It is shown that there exists a linear relationship between the logarithm of adjusted retention time of solute cation and the logarithm of the concentration of eluent cation with a slope of -1. Another equation for the conductivity detection under this conditions is presented. The conductivity change accompanying the elution of a solute cation can be either positive or negative, depending on whether the eluent cation has a high or a low limiting mole ionic conductance. Determination of monovalent cations using inorganic acid (nitric acid), organic acid (citric acid) and aromatic base (aniline) as mobile phase was investigated separately. When an aqueous solution of nitric acid or citric acid was used as mobile phase, the negative chromatographic peaks of solute cation were obtained. When an aqueous solution of aniline was used as mobile phase, the chromatographic peaks of solute cation could be either positive or negative, depending on the relative eluting roles of hydrogen ion and the protonated aniline ion. The linear relationships between the logarithm of adjusted retention time of solute cation and the logarithm of concentration of H + in the mobile phase of nitric acid or citric acid were obtained and the slopes of these relationships were about -1. Li +,Na +, NH + 4,K +, methylamine, ethylamine and n propylamine in snow and well water were determined with nitric acid and citric acid as mobile phase, respectively. The results using nitric acid as mobile phase were in agreement with those using citric acid.Inorganic acids and organic acids are better mobile phases than aromatic base for determination of monovalent cations by single column ion chromatography.