Fehling’s Test- Definition, Principle, Procedure, Result, Uses


Carbohydrates are one of the most important biomolecules that are involved in various metabolic processes and provide energy to living organisms. Carbohydrates can be classified into different types based on their structure and function, such as monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Some carbohydrates have the ability to reduce other substances by donating electrons or hydrogen atoms. These are called reducing sugars and they include glucose, fructose, lactose, maltose, etc. Other carbohydrates do not have this property and are called non-reducing sugars. These include sucrose, starch, cellulose, etc.

Fehling’s test is a simple and widely used chemical test that can differentiate between reducing and non-reducing sugars. It can also be used to identify the presence of aldehydes or ketones in carbohydrates. Fehling’s test is based on the oxidation-reduction reaction between the carbohydrate and a copper (II) complex in an alkaline medium. The test produces a characteristic reddish-brown precipitate of copper (I) oxide if the carbohydrate is a reducing sugar or an aldehyde. If the carbohydrate is a non-reducing sugar or a ketone, the test remains blue and no precipitate is formed.

Fehling’s test has many applications in biochemistry, food science, medicine, and forensic science. It can be used to detect the presence of glucose in urine, which is an indicator of diabetes mellitus. It can also be used to determine the purity of honey by detecting the presence of added sugars. Furthermore, it can be used to identify unknown carbohydrates by comparing their reactions with known standards.

In this article, we will discuss the definition, principle, procedure, result, uses, and limitations of Fehling’s test in detail. We will also explain the reaction involved in Fehling’s test and the requirements for performing it. We hope that this article will help you understand the concept and significance of Fehling’s test better.