15 Questions
What is the expected result of the Seliwanof’s test for fructose?
Positive result in 3 minutes
What is the expected result of the Seliwanof’s test for sucrose?
Positive result in 6 minutes
What is the expected result of the Seliwanof’s test for glucose?
Positive result in more than 7 minutes
What is the expected result of the Seliwanof’s test for lactose?
Positive result in more than 7 minutes
What is the minimum concentration of fructose (ketose) the Seliwanof’s test can detect?
0.1 gm%
What is the expected result of the Seliwanof’s test for a disaccharide containing both glucose and fructose?
Positive result after 6 minutes
In the Seliwanof’s test, what is the expected result for a monosaccharide that is an aldose?
Positive result after 3 minutes
What is the expected result of the Seliwanof’s test for a disaccharide that contains only glucose?
Negative result
Which monosaccharide is expected to take the longest time to give a positive result in the Seliwanof’s test?
Galactose
If a sample gives a positive Seliwanof’s test result after more than 20 minutes, what type of sugar(s) could be present in the sample?
Both ketose and aldose
Which disaccharide would be expected to give a positive Seliwanof’s test result after more than 20 minutes?
Lactose
If a sample gives a positive Seliwanof’s test result after 6 minutes, what type of sugar(s) could be present in the sample?
Glucose
Which monosaccharide is expected to take the longest time to give a positive result in the Seliwanof’s test?
Glucose
What is the minimum concentration of fructose (ketose) the Seliwanof’s test can detect?
0.1 gm%
Which disaccharide is expected to be digested to monosaccharides of fructose and then dehydrate to give a positive result in the Seliwanof’s test after 6 minutes?
Sucrose
Study Notes
Seliwanoff's Test
- Used to differentiate between ketoses and aldoses in mono and disaccharides.
- Employs HCl as a dehydrating agent and resorcinol as a condensing agent.
- Produces a clear colored solution with intensity proportional to the amount of ketoses.
- Can be coupled with spectrophotometric measurement to quantify the amount of ketoses in a solution.
Reaction Principle
- Involves a dehydration reaction due to the hydroxyl groups of the sugar.
- Seliwanoff's reagent consists of resorcinol in dilute hydrochloric acid.
- Ketoses (e.g., fructose) are more readily dehydrated by HCl than aldoses, forming hydroxymethyl furfural.
- Hydroxymethyl furfural condenses with resorcinol to form a red-colored complex.
Test your knowledge of Seliwanoff’s test, used in biochemistry to differentiate between ketoses and aldoses in mono and disaccharides. Learn about the reagents used and the specific properties of the reaction.
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