PAS is used in histology to stain carbohydrate-rich macromolecules such as glycogen, glycoprotein and proteoglycans, commonly found in connective tissue, basal laminae, fungi and certain bacteria.
Periodic acid–Schiff (PAS) is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids and mucins in tissues.
Periodic acid reacts with various polyhydroxy compounds to produce aldehydes and organic acids, and if these com- pounds contain a terminal CH,OH group, formaldehyde is produced.
Periodic Acid Solution (PAS)is recommended to be used along with S074 (Schiff's Reagent) to detect aldehyde, glycogen and polysachharide in cytological and histological specimen.