Oxidation is often a preparatory step in various staining techniques. For example, in the Periodic Acid-Schiff (PAS) stain, periodic acid oxidizes the 1,2-glycol groups in carbohydrates to aldehydes, which then react with Schiff's reagent to produce a magenta color. This technique is widely used to highlight glycogen, mucins, and other carbohydrate-rich structures.
