Separation of resin acids using cyclodextrin-modified capillary electrophoresis

Area of Science:

• Analytical Chemistry
• Environmental Science
• Separation Science

Background:

• Resin acids are common pollutants in pulp mill effluents.
• Accurate analysis of resin acids is crucial for environmental monitoring.
• Existing methods like HPLC and micellar electrokinetic chromatography have limitations in resolving these compounds.

Purpose of the Study:

• To develop a novel cyclodextrin-modified capillary electrophoresis (CE) method for analyzing common resin acids.
• To achieve rapid and efficient separation of resin acids, including challenging pairs.
• To assess the method's utility for environmental samples like pulp mill effluents.

Main Methods:

• Developed a CE method using a buffer containing methyl-beta-cyclodextrin (MECD) and sulfobutylether-beta-cyclodextrin (SBCD).
• Tested two buffer systems: pH 4.5 (sodium acetate) and pH 9.25 (sodium borate), with varying cyclodextrin and acetonitrile concentrations.
• Compared the CE method's performance against High-Performance Liquid Chromatography (HPLC) and micellar capillary electrokinetic chromatography (MECC).

Main Results:

• At pH 4.5 with 20 mM MECD and 30 mM SBCD, baseline separation was achieved for most resin acids within 25 minutes.
• At pH 9.25 with 30 mM SBCD and 20 mM MECD, analysis time was reduced to under 12 minutes, with minor exceptions in peak resolution.
• The CE method demonstrated superior resolution compared to HPLC and MECC for the analyzed resin acids.

Conclusions:

• Cyclodextrin-modified CE provides a rapid and effective method for separating complex mixtures of resin acids.
• The developed CE technique is suitable for the characterization of resin acids in environmental matrices.
• This method offers a valuable tool for environmental monitoring and analysis of industrial effluents.