Identification and interaction of amino acids with leucine-anthracene reagent by TLC and spectrophotometry: experimental and theoretical studies

A new reagent has been synthesized by coupling anthracene moiety to L-leucine. The reagent is characterized by different analytical techniques. It is capable for easy identification of various amino acids on thin-layer chromatography plates by developing distinguishable colors (detection limit between 0.1-0.5 μg at cold condition and 0.1-0.4 μg after heating). This reagent also binds with different amino acids very strongly in solution (methanol). Estimation of equilibrium binding constants of this new reagent with different amino acids has also been carried out. The values of the binding constants are lowest for L-Tyrosine (6.86 × 103 dm3 mol(-1)) and highest for L-Arginine monohydrochloride (8.86 × 10? dm3 mol(-1)) at 25°C. A theoretical study (Hartree-Fock) has been performed to investigate the interaction of the reagent with a representative amino acid, glycine.