The key difference between Anthrone and Molisch test is that Anthrone test can be used to detect carbohydrates using the blue-green color, whereas Molisch test can be used to detect carbohydrates using the violet color.
Anthrone test is a rapid and convenient analytical test for the quantification of carbohydrates that occurs as either free or bound to any lipids or proteins. Molisch test, on the other hand, is an analytical test that is useful in detecting the presence of carbohydrates depending on the dehydration of the carbohydrate by sulfuric acid in the test reagent.
CONTENTS
1. Overview and Key Difference
2. What is Anthrone Test
3. What is Molisch Test
4. Anthrone vs Molisch Test in Tabular Form
5. Summary – Anthrone vs Molisch Test
What is Anthrone Test?
Anthrone test is an analytical test for carbohydrates. It is a rapid and convenient method for the quantification of carbohydrates that occurs as either free or bound to any lipids or proteins. This test has two major objectives: to detect the presence of carbohydrates in a given solution and to quantify the concentration of free and bound carbohydrates in a solution.
Figure 01: Anthrone Test Result
According to this test, if a carbohydrate is present in the form of free carbohydrate as polysaccharides, monosaccharides, or bound as in a glycoprotein or a glycolipid, the carbohydrate will be detected by the concentrated acid in the Anthrone reagent. It will first hydrolyze the carbohydrate into component monosaccharides. Then the concentrated acid catalyzes the dehydration of the monosaccharides to form furfural or hydroxyl furfural.
Thereafter, the formed furfural or hydroxyl furfural condenses with two molecules of naphthol from the Anthrone reagent to give a blue-green complex. As the final step, we can quantify the complex formed by measuring the absorbance using a spectrophotometer under 620 nm wavelength or in a red filter colorimeter.
The Anthrone reagent used in this test is made from dissolving 2 grams of Anthrone in one liter of concentrated sulfuric acid. We need to use a freshly prepared reagent for this assay.
What is Molisch Test?
Molisch test is an analytical test that is useful in detecting the presence of carbohydrates depending on the dehydration of the carbohydrate by sulfuric acid in the test reagent. Sometimes, hydrochloric acid is present in the reagent instead of sulfuric acid. There, the acid can dehydrate the carbohydrate producing an aldehyde. This aldehyde then condenses with two molecules of phenol and gives a violet ring.
Figure 02: Molisch Test
This test was named after Hans Molisch, the Austrian botanist. In the procedure, the test solution has to be combined with a small amount of Molisch’s reagent using a test tube. After this mixing, we have to add a small amount of sulfuric acid down the sides of the test tube, which has to be placed at an angle during this addition. This forms a violet layer to indicate the presence of the carbohydrate.
What is the Difference Between Anthrone and Molisch Test?
Anthrone test and Molisch test are important in detecting carbohydrates in the test sample. The key difference between Anthrone and Molisch test is that Anthrone test can be used to detect carbohydrates using the blue-green color, whereas Molisch test can be used to detect carbohydrates using the violet color.
The below infographic presents the differences between Anthrone and Molisch test in tabular form for side by side comparison.
Summary – Anthrone vs Molisch Test
Anthrone test and Molisch test are two types of analytical tests. The key difference between Anthrone and Molisch test is that Anthrone test can be used to detect carbohydrates using the blue-green color, whereas Molisch test can be used to detect carbohydrates using the violet color.
Reference:
1. “Carbohydrates – the Molisch Test.” Harper College. edu.
Image Courtesy:
1. “Spinach after chromatography” By Kostasmes95 – Own work (CC BY 4.0) via Commons Wikimedia
2. “Próba Molischa” By Kala Nag – Own work (CC BY-SA 4.0) via Commons Wikimedia