Chromatographic, mass spectral, and visible light absorption characteristics of toluidine blue O and related dyes..
Contrary to earlier literature reports, the impurities in toluidine blue O were shown by column chromatography, TLC, and mass spectrometry to be N-methyl homologs of 2-methylthionine rather than N-methyl homologs of thionine. Small amounts of 2-methyl-3-amino-7-methylaminophenothiazine and 2-methyl-3,7-diaminophenothiazine were identified in commercial samples of toluidine blue O. However, sample handling and a warm alkaline environment can cause rapid demethylation of the dye.
D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D004396:Coloring Agents / Q000032:analysis*; D003640:Dealkylation; D004355:Drug Stability; D006358:Hot Temperature; D013058:Mass Spectrometry; D010640:Phenothiazines / Q000032:analysis; D013053:Spectrophotometry; D014048:Tolonium Chloride / Q000031:analogs & derivatives / Q000032:analysis*
D004396:Coloring Agents; D010640:Phenothiazines; D014048:Tolonium Chloride