Ultrasonic Characterisation of Amino Acid Solutions: A Comparative Analysis of Molecular Interactions

The use of ultrasonic techniques offers a non-invasive approach to investigating the molecular interactions affecting the behavior of amino acids in an aqueous medium. In this paper, three amino acids, namely L-leucine, L-isoleucine, and L-histidine, have been investigated in aqueous solutions using ultrasonic technique in presence and absence of electrolytes. Various thermo-acoustic parameters, such as isentropic compressibility, acoustic impedance, intermolecular free length, and relative association have been calculated from density and ultrasonic velocity data. The comparative approach used in this study helps in understanding the effect of side chain hydrophobicity and electrolyte on solute-solvent and solute-solute interactions. It has been observed that side chains with hydrophobic nature reduce the phenomenon of electrostriction and make the structure making process easier, while electrolytes enhance ion-hydrophilic interactions.