SCOTT’s Solution

Scott's solution is a bluing solution used in histology to intensify the staining of cell nuclei and basophilic structures in tissue sections after hematoxylin staining. It consists of a mixture of water, magnesium sulfate (epsom salt), and sodium bicarbonate.

The main function of Scott's solution is to provide magnesium ions (Mg²⁺) that contribute to the formation of coordination complexes with oxidized hematoxylin (hematein). The resulting reaction is:

Hematein + Mg²⁺ → Mg-hematein complex (blue)

The formation of this blue Mg-hematein complex leads to more intense and contrasting staining of cell nuclei and basophilic structures in histological specimens.

The application of Scott's solution follows hematoxylin staining. The stained tissue sections are briefly immersed in the solution to assist the bluing reaction.
The sections are then rinsed in distilled water and further processed, e.g., by counterstaining, dehydration, and mounting. Scott's solution is an important component in routine histology to allow improved staining and thus clearer visualization of cell structures.