During the Gram stain process, after rinsing with water, what is used as a mordant?

In the Gram staining process, a mordant is used to enhance the binding of the dye to the bacterial cells. After the initial step of staining with crystal violet, the cells are rinsed with water, and then Gram's iodine is applied. This iodine forms a complex with the crystal violet, precipitating it within the cell walls and thus intensifying the color of Gram-positive bacteria. This step is crucial, as it helps determine whether the bacteria will retain the crystal violet stain after they are subjected to a decolorizing agent.

The role of iodide enhances the staining process by not only creating a more stable association between the dye and the bacterial cell walls but also clarifying distinctions between different types of bacteria based on their cell wall structures during subsequent steps. This is essential for accurate interpretation of the Gram stain results, which is pivotal in microbiology for the identification and classification of bacterial species.