METACHROMASY - THE INTERACTIONS BETWEEN DYES AND POLYELECTROLYTES IN AQUEOUS-SOLUTION

The literature on metachromasy is reviewed and two quantitative analytical methods for poly(acrylate-co-acrylamide) based on the metachromatic effect are proposed. The color-array method allows for the visual determination of polymer concentration by observing the color of toluidine blue O, cresyl violet acetate, or safranine O at various P/D (polymer acrylate residue to dye molecule) ratios. An abrupt color change is observed at P/D = 1. The complexation-extraction method is based on the removal of the dye janus green B from solution by complexation with poly (acrylate-co-acrylamide) followed by extraction with 1,1,2-trichlorotrifluoroethane (Freon) solvent. Typical concentration ranges for both tests were 0-10 ppm polymer (0-7.4 X 10(-5) M acrylate residue) and 1-6 X 10(-5) M dye.