Formalin is typically prepared as a 10% solution of formaldehyde in water, often referred to as 10% neutral buffered formalin (NBF). The buffering agents, usually sodium phosphate, help maintain a neutral pH, which minimizes tissue damage and preserves antigenicity. Formalin should be stored in a cool, dark place to prevent degradation and to avoid the formation of formic acid, which can damage tissues.
