Lancenigo di Villorba (TV), Italy
===> QUESTION
How do I analyse which sugars are present in lemonade? (such as fructose, sucrose, glucose)?
Please help. Can I use chromatography paper and put drops of the sugar alongside the lemonade drop and see which ones run up the paper? Help!! Thanks.
===> LEMONADE
Lemonade differs by juice squeezed out by lemon-fruits, reader imagine that the nature of sugars contained in lemonade depend strongly on its feature : was fructose added in it? What about glucose and sucrose
The reader has to know that three cited sugars (fructose, sucrose, glucose) are related by the a chemical reaction known as BREAKING/MAKING OF GLYCOSIDIC BOND
Fructose + Glucose
-> Sucrose + Water
so he may think that lemonade is an acidic liquid which promotes the Hydrolysis of Sucrose (follow the leftward arrow) to make Fructose asides Glucose.
Moreover, the notation remembers that Hydrolysis obeys to reversible feature, then Sucrose stay besides Glucose and Fructose.
===> EXPERIMENTAL WAYs
Reader suggested an application of chromatographic separation on an appropriated support ; he has to remember that those three analytes haven't any colorations then CHROMATOGRAPHY CAN'T HIGHLIGHT ANY SEPARATION WHEN IT OCCURRED.
Now, reader has to study lemonade by several essays able to distinguish three sugars, he may look for the following ones :
SCHIFF TEST, an appropriated reactant (sulphurous solution of Fuchsin) turns purples when it meet aldehydic compounds as Glucose is ;
SELIWANOFF TEST, an acidic solution of Resorcinol get a sample of the analyte (lemonade) and this mixture has been warmed gently until it acquires dirty-reddish tint, there is Fructose if the change occurs faster than some minutes ;
TEST ARE REPEATED ON A SECOND LOT OF LEMONADE WHICH HAS BEEN TREATED BY ACIDS THEN LONG WARMING, so when reader note a clear strenghtening of Schiff and Seliwanoff essays this suggest that there was also Sucrose which has been hydrolized by its largest part.
I hope this helps you.
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