Identification of amino acids on thin layer chromatograms by modified ninhydrin reagent

Natural Product Laboratory, Department of Chemistry, The University of Burdwan, Burdwan-713 104,

West Bengal, India

E-mail : sinhababu04@yahoo.co.in Fax : 91-342-2530452/2634200

Manuscript received online 17 April 2013, revised 19 July 2013, accepted 19 July 2013

Spray reagents are very useful for detecting amino acids on thin layer chromatoplates. It is well known that ninhydrin is most widely used as a spray reagent for identification of amino acids due to its high sensitivity, although it produces same purple/violet color with all amino acids, except in two cases : proline and hydroxy proline however give a yellow color. A new modified ninhydrin spray reagent (2-furoic acid) with moderately high sensitivity (0.05–1.00 µg) for easy and rapid identification of amino acids on thin layer chromatography plates has been introduced. The reagent is capable of developing various distinguishable colors with many of them. The color pictures of the chromatograms by digital camera are also included to demonstrate the different colors. A probable mechanism for such color formation has also been proposed.