University Chemistry ›› 2021, Vol. 36 ›› Issue (6): 2006036.doi: 10.3866/PKU.DXHX202006036

• Between Teacher and Student • Previous Articles     Next Articles

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

Man He, Beibei Chen, Bin Hu()   

  • Received:2020-06-08 Accepted:2020-06-29 Published:2020-07-22
  • Contact: Bin Hu E-mail:binhu@whu.edu.cn

Abstract:

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.

Key words: Distribution fraction, Dissociation equilibrium constant, Arsenic species, Analytical chemistry

MSC2000: 

  • G64