Hydrochloric acid, 2.5 l, plastic

Molisch’s test:

Molisch’s reagent is added to a diluted sample of monosaccharide and concentrated sulphuric acid is added down the sides of the test tube to form a layer beneath the solution. A purple ring forms at the interface between the layers. Since nucleic acids and glycoproteins also contain monosaccharides, they may react as well.

The Wöhlk reaction is a classic amino test for aldoses (glucose, galactose, lactose, maltose) – it is used to distinguish between aldoses and ketoses and is particularly useful for determining glucose in urine samples. With a few drops of potassium hydroxide solution, known as Wöhlk-Malfatti test; with methylamine instead of ammonia, also known as Fearon’s test.

Reagents required: 10% ammonia solution, sodium hydroxide, hydrochloric acid, diluted, optional

Application: The aldose (such as glucose) reacts with ammonia in an alkaline solution. This results in the formation of an aldimine (reaction of the aldehyde group with ammonia). Subsequent rearrangement produces a coloured amine derivative, often with a red-violet colour.