Optimization of background electrolyte composition for simultaneous contactless conductivity and fluorescence detection in capillary electrophoresis of biological samples

Electrophoresis. 2019 Sep;40(18-19):2390-2397. doi: 10.1002/elps.201900112. Epub 2019 Jun 26.

Abstract

In this article, optimization of BGE for simultaneous separation of inorganic ions, organic acids, and glutathione using dual C4 D-LIF detection in capillary electrophoresis is presented. The optimized BGE consisted of 30 mM 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, 15 mM 2-amino-2-hydroxymethyl-propane-1,3-diol, and 2 mM 18-crown-6 at pH 7.2 and allowed simultaneous separation of ten inorganic anions and cations, three organic acids and glutathione in 20 min. The samples were injected hydrodynamically from both capillary ends using the double-opposite end injection principle. Sensitive detection of anions, cations, and organic acids with micromolar LODs using C4 D and simultaneously glutathione with nanomolar LODs using LIF was achieved in a single run. The developed BGE may be useful in analyses of biological samples containing analytes with differing concentrations of several orders of magnitude that is not possible with single detection mode.

Keywords: Capillary electrophoresis; Contactless conductivity detection; Dual detection; Laser induced fluorescence detection; Saliva.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breath Tests / methods
  • Carboxylic Acids / analysis
  • Carboxylic Acids / isolation & purification
  • Electric Conductivity
  • Electrophoresis, Capillary / methods*
  • Equipment Design
  • Glutathione / analysis
  • Glutathione / isolation & purification
  • Humans
  • Ions / analysis
  • Ions / isolation & purification
  • Limit of Detection
  • Linear Models
  • Reproducibility of Results
  • Spectrometry, Fluorescence / methods*
  • Tears / chemistry

Substances

  • Carboxylic Acids
  • Ions
  • Glutathione