Ultrasonic absorption studies may throw more light on the molecular interactions to know the behavior of biological macromolecules in aqueous solution. It is the key to solve the critical problems with the role and interaction of these substances in living organisms. In this paper, the ultrasonic velocity and absorption measurements were made using Pulse Echo Overlap (PEO) technique at 2 MHz at 298 K in aqueous Arginine and aqueous Methionine. The related parameters relaxation time, classical absorption, excess absorption, volume viscosity has been evaluated. The observed ultrasonic absorption is much higher than the classical absorption. These studies show that the nature of molecular interaction in aqueous solution of biological molecules is complex in nature.
