The Periodic acid solution 0.5% for the PAS reaction(periodic acid Schiff) for the detection of aldehyde and mucosubstances in microscopy, is a ready to use solution used for the detection of mucopolysaccharides, glycogen, muco- and glycoproteins, glyco-, phospholipids, basal membranes and collagen. The material is treated with periodic acid creating aldehyde groups which react with Schiff's reagent and give a bright red color reaction, thus the nuclei appear blue.