ON-PLATE IDENTIFICATION OF AMINO ACIDS WITH PRELIMINARY SEPARATION USING GREEN SOLVENTS

Abstract

A green thin layer chromatography (TLC) has been used as an analytical method for the identification and separation of amino acids through silica static flat bed in contact of n-butyl acetate, n-butyl alcohol, or ethylene glycol and their mixtures. The chromatographic system constituting silica gel as stationary phase, and n-butyl acetate–n-butyl alcohol–ethylene glycol in 3:5:2 ratio (v/v) as mobile phase with solvent ascent 5.0 cm was most favorable for on-plate identification of amino acids (lysine, alanine, and tryptophan) with preliminary separation. The presence of impurities such as metal cations, anions, and vitamins in the sample on the resolution of lysine, alanine, and tryptophan was also examined. The chromatographic parameters like ΔRF, separation factor (α), and resolution (Rs) of separated components of the mixture of these three amino acids were calculated. Densitogram of the separation of lysine, alanine, and tryptophan was recorded. The limit of detection for lysine was 0.6 µg spot−1, whereas for alanine and tryptophan it was 1.0 µg spot−1. The applicability of the proposed method was established by achieving separation from real and spiked pharmaceutical product. The proposed method is rapid and free from the use of volatile organic solvents and is therefore environmentally acceptable.