These reference measurements provided qualitative information on the contribution of the solvents to the mass spectra during cell cycling. CH4, dimethyl ether and 2G vapor were measured for cells with 2G-based electrolytes, propene and PC vapor were measured for cells with PC-based electrolytes. The selection of those gases gave good results. Other gases such as ethane, ethene and propane were considered as well but were excluded from the calculation as they could not be found in the spectra.