alpha-Naphtholphthalein

alpha-Naphtholphthalein is an indicator that is light yellow at pH 6 and gradually shows a clear color change with increasing pH to light green-green-blue. alpha-Naphtholphthalein can be impregnated into cotton-blend fabrics and used to develop medical supplies for wound pH monitoring, such as medical gauze, hospital gowns and compression bandages.