Reagents of Osazone test are 1. Phenylhydrazine mixture consisting of phenyl-hydrazine and anhydrous sodium citrate 2. Orignal solution containing a carbohydrate
For identification purposes the carbonyl and adjacent alcohol functions will form phenylhydrazine derivatives known as osazones, which give characteristic melting points and exhibit definite crystalline structure. It should be noted that glucose , fructose and mannose yield the same osazone since the difference in structure and configuration about carbon atoms 1 and 2 are abolished.
The phenylhydrazine test is also known as the Osazone test. The phenylhydrazine test is used for reducing the amounts of carbohydrates, momosacchstides, and disaccharides.
Glucose, Fructose and Mannose give the same osazone because these sugars have the same configuration of carbons 3, 4, 5 and 6. osazone formation only affects carbons 1 and 2.
osazone test is a carbohydrate specific reaction in which carbs react with phenylhydrazine to form osazones i.e. crystals of specific shape. thus the test confirms the presence of a particular sugar.Eg:for sucrose one gets a mixture of glucosazone and fructosazone on the basis of components of sucrose.
They are both reducing sugars. They have aldose and ketose group at the side of the structure, which helps the sugar to condense with phenylhydrazine and produce solid derivatives called osazone. The solid is seen as crystals through the microscope.
After hydrolysis sucrose did give a positive test. It reduces sugar that has hemiketal and hemiaetal in it.
D-erythrose and D-threose both yield the same osazone. Likewise, L-erythrose and L-threose yield the same osazone.
glucose and fructose form same osazone crystals because carbon no 1 to carbon no 6 are identical both in glucose and in fructose
Anhydrous sodium acetate is added to buffer the phenylhydrazine HCl so that it may function properly. Regards mawaisnawaz@hotmail.com
Once you test your blood sugar, you can figure how much insulin to give yourself. Because your blood sugar varies every time you check, that is why.
Glycoproteins give positive results for Molisch's test. This answer is true because Molisch test was a test for sugar.