Indigo/Dehydroindigo/Palygorskite Complex in Maya Blue:  An Electrochemical Approach

The voltammetry of microparticles methodology is applied to describe the electrochemistry of indigo and Maya Blue, a nanostructured organic−inorganic material, in contact with different MeCN electrolytes. The voltammetric response of synthetic specimens and genuine Maya Blue samples differ significantly from that of indigo microparticles, all being conditioned by the size-dependent insertion of electrolyte ions into the solid. Electrochemical data indicate that formation of Maya Blue involves a significant reorganization of zeolitic and/or structural water of the clay and confirms the presence of dehydroindigo accompanying indigo in the palygorskite matrix.