Alcian yellow as a fluorescent dye

Fluorescence characteristics of the cationic dye Alcian yellow are described. Under ultraviolet excitation, the chromatin and basophilic cytoplasm from cell smears show a blue-white emission, which depends on the presence of nucleic acids. Glycosaminoglycans-containing structures (mast cell granules, cartilage matrix) appear brightly fluorescent. The excitation at 320 less than or equal to lambda less than or equal to 340 nm is the most suitable, and the emission wavelength shows dependence on the dye concentration.