Within Sweden and the EU, an increased use of biogas and natural gas is encouraged. To support more effective manufacturing, distribution, and consumption of energy gases, new methods for the measurement of the calorimetric value or the gas composition are needed. In this paper, we present a method to quantify variation in ultrasound pulse shape, caused by interaction effects between the constituents of a two-component gas mixture. The method is based on a combination of principal component analysis and orthogonal signal correction. Experiments on mixtures of oxygen and ethane show that the extracted information correlates well with the molar fraction of ethane in the mixture.