Aqueous Urea Solution Promoted Resolution of Five-Component Mixture of Amino Acids on Silica TLC Plates

A thin-layer chromatographic system comprising of silica gel as stationary phase and 1.0% aqueous urea solution as mobile phase (pH 7.44) has been developed for the mutual separation of five-component mixture of amino acids [lysine (RF = 0.38), histidine (RF = 0.59), leucine (RF = 0.78), alanine (RF = 0.87), and glutamic acid (0.98)]. The presence of foreign substances such as metal cations, anions, and vitamins as impurities in the sample on the separation was also examined. Thin-layer chromatographic parameters such as standard deviation (SD), ΔRF, separation factor (α), and resolution (RS) values of separated components of the mixture of these five amino acids were calculated. The limits of detection for lysine, leucine, and alanine were found to be 1.5 µg spot−1, whereas for histidine and glutamic acid, these were 1.2 µg and 3.0 µg spot−1, respectively. The proposed TLC system is applicable for the identification and separation of amino acids in pharmaceutical formulations.