Use of lignins as components of background electrolyte in capillary electrophoresis

The electrophoretic behavior of two lignins of different compositions, i.e., spruce dioxane lignin and lignosulfonate, is studied. The lignins are shown to affect the electrophoretic behavior of negatively charged analytes, such as carboxylic acids and phenols; their migration time increases. The addition of lignins improves the analytical parameters of phenol quantification by capillary electrophoresis. By means of a simple non-modified capillary, a mixture of six phenols was separated (simple phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, and perchlorophenol) with the high resolution (up to 20) and efficiency [(1–5) × 10⁵ TPM]. The separation of six phenols takes 10 min, the lower limit of the analytical range makes 1 μg/mL, the relative standard deviation does not exceed 3%. The potency for the determination of simple phenol and m-cresol is shown on an example of the Verrukatsid medication within 7 min.