Abstract: A method for assessing a molecular or isotopic composition of a fluid includes analyzing a proportion of the fluid derived from a source to determine the source of the fluid, quantifying the proportion of the fluid derived from one or more sources, and assessing the relationships of chemical species within the fluid to validate the source of the fluid. This assessment can be accomplished through the direct measurement of molecular composition of fluid mixtures or the isotopic composition of specific fluids in that mixture, and/or a combination of statistical, thermodynamics, or kinetic modelling of these chemical reactions. The results of these measurements and models can be used to verify the source and conditions of various forms of hydrogen or other resources.