Procedures 10. Examine the crystals under low power objective
Results and Discussions The reaction is stepwise;
Osazone formation involves hydrazone formation at C-1 of an aldose (or C-2 of a ketose) and oxidation of C-2 (or C-1) of an alcohol group to a ketone (or an aldehyde). The new carbonyl group is also converted to a hydrazone. Mannose Glucose Fructose
Osazone crystals have a characteristic shape under the light microscope and help in the identification of the sugar type. Monosaccharides - like needle-shaped or broomstick Disaccharides - like sunflowers Lactose - like tight balls of needles
Making Osazone Crystals The difference in the structure of the monosaccharides is caused by the diverse groups attached to the first and second carbons of the sugar molecules. Their needle-shaped crystals show that the position of the first and second carbons do not matter in the crystal formation.
Time to Form The time needed to create osazone crystals varies among the various sugars involved, but helps to identify the sugars being tested. For an osazone crystal to be presented from a hot solution will take as long as follows: