You can use this small and simple freeware program to calculate compositions of C-O-H fluid at pressures from 1 bar to 100 kbar and temperatures from 400°C to 2300°C for many samples at once, according to: Zhang, C., Duan, Z.H., 2009. A model for C–O–H fluid in the Earth’s mantle // Geochimica et Cosmochimica Acta, V. 73, pp. 2089–2102...