Isatin Test- Definition, Objectives, Principle, Procedure, Result, Uses


Isatin test is a biochemical test that can detect the presence of certain amino acids, namely proline and hydroxyproline, in a sample. These amino acids are also known as imino acids because they have an imino group (-NH-) instead of an amino group (-NH2) in their structure. Proline and hydroxyproline are important components of proteins, especially collagen, which is the main structural protein in connective tissues.

The isatin test is based on the reaction between isatin and imino acids, which produces a blue-colored compound called an adduct. Isatin is a chemical compound that has the formula C8H5NO2 and the structure shown below:

The isatin test can be performed on a filter paper or a thin-layer chromatography (TLC) plate, where a drop of the sample containing imino acids is applied and then treated with the isatin reagent. The formation of a blue spot indicates a positive result, while the formation of a pink spot indicates a negative result.

The isatin test is a simple, fast, and specific method for the detection and estimation of proline and hydroxyproline in various samples, such as biological fluids, plant extracts, food products, and environmental samples. The test can also distinguish proline and hydroxyproline from other amino acids that do not react with isatin. However, the test cannot differentiate between proline and hydroxyproline, as both produce the same blue color with isatin.

Some possible ways to end this point are:

  • In this article, we will discuss the objectives, principle, procedure, result, uses, and limitations of the isatin test in detail.
  • The isatin test has many applications in biochemistry, biotechnology, food science, and environmental science. In the following sections, we will explore the various aspects of this test in more depth.
  • The isatin test is one of the most reliable and convenient methods for the detection of imino acids. To understand how this test works and what it can be used for, let us first look at the objectives and principle of the test.