Gram’s Iodine, 33% is a concentrated solution used as a mordant (fixative) in the Gram staining procedure for bacteria. It enhances the retention of crystal violet dye in Gram-positive organisms by forming a crystal violet–iodine complex inside the cell wall.
Applications
• Gram staining: Acts as a mordant, fixing crystal violet dye in Gram-positive bacteria.
• Microbiology labs: Standard reagent for bacterial differentiation.
• Histology: Occasionally used as a tissue stain enhancer