Sudan IV in ethylene glycol is a staining solution primarily used in histology and cytology. Sudan IV, also known as Fat Red 7B or Solvent Red 24, is a lipophilic dye used to selectively stain lipids and fatty structures in tissue specimens.

In this case, the Sudan IV solution is dissolved in ethylene glycol, a less volatile solvent than alcohol. Ethylene glycol allows effective penetration of the dye into the lipid structures and facilitates the staining process while reducing solvent evaporation. This can be advantageous in some cases to achieve slower and more controlled staining of lipids.

Sudan IV staining is commonly used to analyze adipose tissue, to study atherosclerosis, or to identify fat-containing cells in cell cultures. Sudan IV binds to nonpolar lipids and allows clear differentiation of these structures from the aqueous components of the tissue.

This Sudan IV stain in ethylene glycol is specifically designed for professional use in histology laboratories and provides a reliable and efficient method for staining lipids in tissue sections and cell preparations.