1.1 ,This test method describes a procedure for total hydrocarbons (THC) measurement in hydrogen intended as a fuel for fuel cells on a methane (C1) basis. The determination of total hydrocarbons on a C1 basis is an analytical technique where all of the hydrocarbons are assumed to have the same response as methane. Sensitivity from 0.1 part per million (ppm(v), µ,mole/mole) up to 1000 parts per million (ppm(v), µ,mole/mole) concentration are achievable. Higher concentrations can be analyzed using appropriate dilution techniques. This test method can be applied to other gaseous samples requiring analysis of trace constituents provided an assessment of potential interferences has been accomplished.