Periodic acid 1% solution is an aqueous solution containing 1% periodic acid (HIO4). It is widely used in histology and histopathology. The solution serves as an oxidizing agent and plays an important role in periodic acid-Schiff (PAS) staining.

PAS staining is used to detect glycogen, neutral mucous substances, basement membranes and other polysaccharides in tissues. The periodic acid oxidative cleaves these compounds, releasing aldehyde groups that subsequently react with the Schiff reagent. This reaction results in a magenta staining visible under the microscope.

PAS staining is an important diagnostic method used in various areas of pathology and histology. It is particularly useful in the study of glycogen-storing diseases, certain tumors, mucopolysaccharidoses, and other disorders associated with the accumulation of polysaccharides in tissues.
When working with periodic acid 1% solution, care should be taken that the solution is highly oxidizing and should be handled with appropriate caution.