Insight into the Heparin–Toluidine Blue (C.I. Basic Blue 17) interaction

Heparin–Toluidine Blue (C.I. Basic Blue 17) interaction was studied using UV–vis spectroscopic analysis of the titration of the functional groups present on the polyanion chain. The study took into consideration both the pH and relative amount of the dye as a function of the Heparin repeat unit number; formation of a dye/polysaccharide aggregate was studied under the same conditions and structural models of the two types of aggregates were proposed. As a consequence of such an investigation a new Heparin determination methodology was developed.