Abstract Hydrogen solubility in CO 2 -expanded 2-propanol and in propane-expanded 2-propanol was obtained by an acoustic technique described elsewhere [L. Zevnik, J. Levec, Gas expanded liquids: Determination of the volumetric expansion by an acoustic technique, J. Supercrit. Fluids (2007), in press]. Solubility in CO 2 -expanded 2-propanol at expansion coefficients V / V 0 = 2 and 4 was determined at 298 and 313 K. H 2 solubility was determined also in liquid CO 2 at 298 K and partial pressure of H 2 up to 6 MPa. Solubility in propane-expanded 2-propanol with V / V 0 = 2 and 4 was measured at 333, 353 and 393 K. Hydrogen mole fraction in liquid propane was obtained at 333 K and partial pressure of H 2 up to 5 MPa. For both expanded liquids the results show that hydrogen concentration increases with increasing V / V 0 ratio and with increasing temperature. It is demonstrated, however, that the acoustic technique is a reliable method for determination of gas composition and that it can be also implemented in various fields of gas processing.