Robin, You have backed into what I have been saying all along i.e. that there is way to little hydrogen available for a substantial part of what is reported not to be 13C...
ie. the H:C ratio is 10:14 at best - but since in the table near the end of the experiment, he sees some methane, some CH3 and other aromatic compound which take away the small amount of H which is there at the beginning -- then the tiny amount of hydrogen left over is simply not enough to account for the fact that something like 10^20 atoms of 12C must have been converted to 13C. Jones
