  An unavoidable category of molecular species in large-scale tritium
applications, such as nuclear fusion, are tritium-substituted hydrocarbons;
these form by radiochemical reactions in the presence of (circulating) tritium
and carbon (mainly from the steel of vessels and tubing). Tritiumsubstituted
methane species, CQ$_4$ (with Q = H , D , T), are often the precursor for
higher-order reaction chains, and thus are of particular interest. Here we
describe the controlled production of CQ$_4$ carried out in the CAPER facility
of the Tritium Laboratory Karlsruhe (TLK), exploiting catalytic reactions and
species-enrichment via the CAPER-integral permeator. CQ4 was generated in
substantial quantity (>1000 cm$^3$ at ~850 mbar, with CQ$_4$ - content of up to
~20 %). These samples were analyzed using laser Raman and mass spectrometry, to
determine the relative isotopologue composition and to trace the generation of
tritiated chain-hydrocarbons.
