Determination of Acid Dissociation Constants of Degradable Catecholamines by CZE

• ITOH Daichi

  Department of Chemical Science and Technology, Graduate School of Advanced Technology and Science, Tokushima University

• MIZUGUCHI Hitoshi

  Department of Applied Chemistry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University

• TAKAYANAGI Toshio

  Department of Applied Chemistry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University

Bibliographic Information

Other Title

• キャピラリーゾーン電気泳動法によるカテコールアミン類の酸解離定数の決定
• キャピラリーゾーン デンキ エイドウホウ ニ ヨル カテコールアミンルイ ノ サン カイリ テイスウ ノ ケッテイ

Abstract

The acid dissociation constants (pK_a) of four catecholamines were determined through changes in the effective electrophoretic mobility by capillary zone electrophoresis (CZE). The catecholamines are degradable in alkaline aqueous solutions, and the CZE peaks corresponding to the degraded species from the catecholamine were detected in the electropherogram. Although the peak height of the catecholamine in the electropherogram decreased under alkaline pH conditions, the acid dissociation constants of catecholamines were determined based on the peak of the catecholamine detected. The effective electrophoretic mobility of dopamine (μ_eff,DA), as an example, was positive at weakly acidic to weakly alkaline pH conditions, suggesting that dopamine was positively charged by protonation. The μ_eff,DA value decreased with increasing pH of the separation buffer, and the value was negative at alkaline pH conditions of pH > 10; the protonated dopamine dissociates at two steps, and it becomes anionic. Two steps of the acid dissociation constants were determined through changes in the effective electrophoretic mobility; pK_a1 = 9.12±0.03 and pK_a2 = 10.85±0.16 were determined for dopamine.

Journal

• BUNSEKI KAGAKU

  BUNSEKI KAGAKU 68 (11), 871-876, 2019-11-05

  The Japan Society for Analytical Chemistry

Keywords

• catecholamines
• acid dissociation constants
• capillary zone electrophoresis
• degradable compounds

Details

• CRID: 1390283659826515328
• NII Article ID: 130007759836
• NII Book ID: AA11681958
• DOI: 10.2116/bunsekikagaku.68.871
• NDL BIB ID: 030096815
• ISSN: 05251931
• Web Site: https://repo.lib.tokushima-u.ac.jp/114228
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I030096815
• Web Site: https://www.jstage.jst.go.jp/article/bunsekikagaku/68/11/68_871/_pdf
• Text Lang: en
• Data Source:
  • JaLC
  • IRDB
  • NDL
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed