Last week I had my first Biochemistry practical which basically carbohydrate testing. Since my high school years doing biology labs I was always fascinated when performing food tests. The colours observed when various test was carried out was the highlight of these experiments.
I had the privilege of carry out the Molisch Test on glucose, maltose, arabinose, sucrose and starch solutions.All sugars undergo dehydration reactions in the presence of sulfuric acid to form 5-hydroxymethylfurfural (or furfural) then this reacts with alpha-naphthol to form a coloured product.
1.This test was carried out by adding a few drops of one of the solutions eg.sucrose to be tested in a test tube.
2.2ml of Molisch reagent was added and the contents was mixed.
3. The test tube was inclined to allow 1ml of concentrated sulphuric acid down the side of the test tube.
4. A reddish-violet colour between the junctions of the two liquids would then appear if the test was positive.
Also remember when carrying out Laboratory practicals be safe and always remember your PPE…
Happy testing…enjoy your weekend 🙂
Photo reference :