LINEAR-POLYMERS APPLIED AS PSEUDO-PHASES IN CAPILLARY ZONE ELECTROPHORESIS OF AZO-COMPOUNDS USED AS TEXTILE DYES

Nine synthetic organic dyes, including seven azo compounds, used as colouring matter for textiles were separated as anions by capillary zone electrophoresis. As most of the solutes are sulfonic acids, the separation could not be effected by varying the pH of the buffer solution. Therefore, two methods were applied to adjust the electrophoretic mobility in a specific way: complexation by bis-tris-propane and interaction with linear polymers added to the buffer and acting as pseudo-phases. A buffer system containing polyethylene glycol and polyvinylpyrrolidone permits the separation of all analytes. Retention of the dyes caused by the polymeric additives was related to the solute's structure. It was demonstrated by cluster analysis that the relative decrease in the electrophoretic mobility of the dyes correlates with the number of benzoaromatic rings in the solute molecules.