Ultrasonic absorption in aqueous solutions of chondroitin sulfate

Ultrasonic absorption and velocity were determined in aqueous solutions of chondroitin sulfate, the major sulfated mucopolysaccharide which is distributed throughout mammalian connective tissue, as a function of ultrasonic frequency (2.39-62.4 MHz), temperature (10•-37•C), and pH (0.85-13.3). A broad distribution of relaxation frequencies is required to describe the absorption spectra. The apparent activation energy is 3.7 kcal/mole at a concentration of 0.054 gm/cc and at neutral pH over the frequency range 8.87-50.5 MHz. It is suggested that the same absorption mechanism(s) may be responsible in aqueous solutions of chondroitin sulfate and dextran at neutral pH. The absorption peaks near pH 2.5 and 11.5 are typical of those observed for the proton-transfer mechanism.