121st General Meeting of the KCS

Type Poster Presentation
Area Analytical Chemistry
Room No. Event Hall
Time 4월 19일 (목요일) 11:00~12:30
Code ANAL.P-253
Subject Physicochemical properties of solvents background electrolytes for predictability of elution order of organic dyes in non-aqueous capillary electrophoresis
Authors Minjeong Gu, GeonBok Lee1, Seong Ho Kang1,*
Department of Chemistry, Kyung Hee University, Korea
1Department of Applied Chemistry, Kyung Hee University, Korea
Abstract The predictability of elution order of organic fluorescent dyes (i.e., crystal violet, methyl violet base, methyl violet B base, rhodamine 6G, and rhodamine B base) in non-aqueous capillary electrophoresis (NACE) was investigated by focusing on the physicochemical properties of various organic solvents [ethanol, methanol, 2-propanol, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO)] in background electrolyte (BGE). As seen in conventional aqueous BGE, the mobility of EOF in organic solvents tended to rise when the ratio between the dielectric constant and the solvent’s viscosity (ε/η) increased in accordance with Smoluchowski’s equation. However, unlike the ε/η of pure organic solvents, the elution order of dyes changed as follows: methanol (60.0) > DMF (45.8) > ethanol (22.8) > DMSO (23.4) > 2-propanol (9.8). Since the amount of acetic acid added to balance the pH depends on the pKa of each solvent, EOF changed when the difference in the ε/η value was small. This resulted from the inhibition of mobility, and its difference was dependent on the ε/η of BGEs with high ionic strength. In particular, the actual mobility of dyes in DMF showed excellent compliance with the Debye-Hückel-Onsager (DHO) theory extended by Falkenhagen and Pitts, which enabled us to analyze all dyes within 15 min with excellent resolution (Rs > 2.5) under optimum NACE conditions (10 mM sodium borate and 4661 mM acetic acid in 100% DMF, pH 4.5). In addition, the NACE method that was developed could be applied successfully to the analysis of commercially available ballpoint ink pens. Thus, these results could be used to anticipate the elution order of organic dyes in a 100% NACE separation system.
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