The 3% alcoholic iodine solution is an essential reagent in microbiology, especially in Gram staining. In this staining procedure, it serves as a mordant that stabilizes the staining of bacterial cell walls by crystal violet. This occurs through the formation of a water-insoluble complex between the iodine ions and the crystal violet molecules, which anchors itself within the thick peptidoglycan layers of Gram-positive bacteria. Thus, the solution provides indispensable support for the differentiation of bacterial species.

In addition, iodine is characterized by its strong oxidizing action, which provides antimicrobial activity. By oxidizing proteins and nucleic acids, it can affect the vitality of microorganisms. Although it is not the main application of the product in this regard, it broadens the range of possible uses.

The solution is dissolved in 99% ethanol, which ensures high purity and stability. This distinguishes it from similar products and ensures reliable and precise scientific application. Here, the specific chemical properties and reactions of iodine are crucial for the functionality of the solution.