Metachromasia Induced in Cationic Dyes by Iodide Salts

Amitabha Saha

Abstract: Inorganic salts like NaI and KI induce distinct metachromasia in thiazine dye 1, 9-dimethylmethylene blue (DMMB, 2.0X10-5M) and cyanine dye pinacyanol chloride (PCYN, 2.0X10-5M). Half plateau values signifying destruction of metachromatic compounds to the extent of 50 % correspond to Ì´22 %, and Ì´30 % ethanol for DMMB-NaI, and PCYN-NaI systems respectively. Conductometric titrations reveal that DMMB and PCYN bind with NaI in the molar ratio of 1: 1

Keywords: Metachromasia, Chromotrope, α-band, β-band, µ-band