A method for analyzing the composition of a multi-component matter sample comprising: determining a first composition of a multi-component matter sample using a spectroscopic device; calculating a relative composition matrix containing a normalized molar amount of each component of the matter sample, based on the first composition; calculating a value of a first secondary property of the matter sample using the relative composition matrix; measuring a value of the first secondary property of the matter sample with a sensor embodied to measure the value of the first secondary property, wherein the first secondary property is thermal conductivity, wherein the resolution of the thermal conductivity measuring device is greater than the contribution to thermal conductivity that a component invisible to the spectroscopic device provides; and determining whether a first difference between the calculated value of the first secondary property and the measured value of the first secondary property exceeds a first threshold, wherein upon determining that the first difference exceeds the first threshold: attributing the first difference to the component invisible to the spectroscopic device; calculating a first amount of the spectroscopic-invisible component using the first difference; adding the first amount of the spectroscopic-invisible component to the relative composition matrix; and adjusting the normalized molar amount of each component in the relative composition matrix to account for the first amount of the spectroscopic-invisible component. determining a first composition of a multi-component matter sample using a spectroscopic device; calculating a relative composition matrix containing a normalized molar amount of each component of the matter sample, based on the first composition; calculating a value of a first secondary property of the matter sample using the relative composition matrix; measuring a value of the first secondary property of the matter sample with a sensor embodied to measure the value of the first secondary property, wherein the first secondary property is thermal conductivity, wherein the resolution of the thermal conductivity measuring device is greater than the contribution to thermal conductivity that a component invisible to the spectroscopic device provides; and determining whether a first difference between the calculated value of the first secondary property and the measured value of the first secondary property exceeds a first threshold, wherein upon determining that the first difference exceeds the first threshold: attributing the first difference to the component invisible to the spectroscopic device; calculating a first amount of the spectroscopic-invisible component using the first difference; adding the first amount of the spectroscopic-invisible component to the relative composition matrix; and adjusting the normalized molar amount of each component in the relative composition matrix to account for the first amount of the spectroscopic-invisible component. attributing the first difference to the component invisible to the spectroscopic device; calculating a first amount of the spectroscopic-invisible component using the first difference; adding the first amount of the spectroscopic-invisible component to the relative composition matrix; and adjusting the normalized molar amount of each component in the relative composition matrix to account for the first amount of the spectroscopic-invisible component. <EOS>