Iodine Test- Definition, Principle, Procedure, Result, Uses


The iodine test is a simple and widely used chemical test to detect the presence of certain types of carbohydrates in a sample. The test is based on the reaction of iodine with starch, a polysaccharide composed of long chains of glucose units. Starch forms a blue-black or purple complex with iodine, which can be easily observed by the naked eye. Other polysaccharides, such as dextrin and glycogen, also react with iodine but produce different colors. Monosaccharides and disaccharides, such as glucose and sucrose, do not react with iodine and remain colorless.