Seliwanoff''s Test - Qualitative Test for Carbohydrates

Summary

This video explains the process of Civano's test, used to distinguish between aldose and ketose sugars. The test involves dehydrating sugars in the presence of concentrated acids to produce ferals or derivatives that react with rosinol in Civano's reagent, forming a cherry-red complex as a positive result. The procedure includes preparing test tubes with fructose and glucose, adding Civano's reagent, mixing, and heating the solution for 30 seconds in a water bath. The results are then observed for the color change, indicating the presence of either aldose or ketose sugars.

Takeaways

• 😀 The test differentiates between Aldose and Ketose sugars.
• 😀 Civano's reagent is used to test for ketose sugars.
• 😀 Ketose sugars (e.g., fructose) react with concentrated acids to form derivatives that produce a positive result.
• 😀 A positive result is indicated by a cherry red colored complex when reacted with Civano’s reagent.
• 😀 The test uses a water bath to heat the test tubes for exactly 30 seconds.
• 😀 Materials needed include Civano’s reagent, glucose, fructose, pipet, test tubes, and a measuring cylinder.
• 😀 1 mL of the test solution should be pipetted into labeled test tubes.
• 😀 5 mL of Civano’s reagent should be added to each test tube after the sugar solution.
• 😀 After mixing, the solution is heated in a water bath for 30 seconds and then cooled.
• 😀 After cooling, the color change (cherry red) is observed to confirm a positive reaction for ketose sugars.

Q & A

What is the main purpose of the Civano's test?

The Civano's test is used to distinguish between aldose sugars and ketose sugars, specifically to identify ketosis from osis in sugars.

What happens to keto sugars during the Civano's test?

Keto sugars dehydrate in the presence of concentrated acids, yielding furans or their derivatives. These react with the Rosinol in Civano reagent, resulting in a cherry-red colored complex, which is the positive test result.

What are the key materials used in Civano's test?

The key materials include Civano reagent, fructose, glucose, a pipette, test tubes, and a measuring cylinder.

What is the first step of performing the Civano's test?

The first step is to pipet 1 milliliter of each test solution into labeled test tubes.

How much Civano reagent is added to each test tube?

Add 5 milliliters of Civano reagent to each test tube after the test solutions.

How long should the test tubes be heated during the Civano's test?

The test tubes should be heated for exactly 30 seconds in a water bath.

What should you do after heating the test tubes in Civano's test?

After heating, cool the test tubes and observe the reaction for the presence of a cherry-red color, indicating a positive result.

What is the significance of a cherry-red complex in the Civano's test?

The appearance of a cherry-red complex indicates a positive result, suggesting the presence of ketose sugars or a ketosis state.

Why is it important to label the test tubes in Civano's test?

Labeling the test tubes ensures that each test solution is correctly identified and prevents any mix-up during the experiment.

How should the test results be interpreted in Civano's test?

A cherry-red color indicates a positive result, while the absence of the color suggests a negative result, meaning the test solution does not contain ketose sugars.