基于砷形态的分离/富集加深学生对“分布分数”的理解

Deepen the Understanding of“Distribution Fraction”with Separation/Enrichment of Arsenic Species as Examples

基于六种砷形态(砷酸、亚砷酸、单甲基砷酸、二甲基砷酸、砷胆碱和砷甜菜碱)的解离平衡常数和不同pH条件下的分布分数信息,对它们在色谱/非色谱分离中的保留行为差异、以及在吸附材料上实现同时富集的可能原因进行了探讨。并以此为例,强化分析化学教学过程中对“分布分数”这一基本概念的讲授,以达到加深认知、牢固掌握、激发兴趣的教学目的。

Based on the dissociation equilibrium constants of six arsenic species,including arsenic acid,arsenite,monomethyl arsenate,dimethylarsenic acid,arsenicone and betaine,and corresponding distribution fraction at different pH,the retention differences in chromatographic/non chromatographic separation process,and the possible reasons for simultaneous enrichment of these species are discussed.It was used as an example to improve the teaching of the basic concept of“distribution score”in the course of analytical chemistry,and to achieve the teaching goal of deepening cognition,firmly mastering and stimulating interest.