Identification of free amino acids in several crude extracts of two legumes using thin-layer chromatography

Amino acids are primary metabolites and nutritional organic compounds that are the building blocks of proteins [1]. The standard (proteinogenic) amino acids consist of an amine group (NH2), a carboxylic acid (COOH), α hydrogen, and a side chain [2]. Thin-layer chromatography (TLC) is a simple, qualitative, sensitive, and widely used method for the separation and identification of amino acids in plant extracts. Amino acids vary in their solubility in water and organic solvents depending on the nature of their side chains; water-soluble amino acids have polar side chains [3].