My recollection is that activated alumina packed columns were typically used for separation of hydrogen isotopes. Examples used to be in old catalogues from packed column suppliers ( 1970s -1980s )
There are also alumina plot columns available, but I would start with a packed column. There should be plenty of literature from the 1960s and 1970s when many such isotope studies were performed.
Alumina chromatography behaviour is categorised by Brockmann activity ( mainly a function of residual water, IIRC ), so it would be very good idea to perform a literature search for the specific details of column preparation for the analysis.
Later Edit - An alternative technique is to use cryogenic conditions ( if your Gc supports them ), eg Molecular Sieve columns at liquid nitrogen temperatures. In my experience, cyrogenic conditions tend to be much more noisy ( both baseline and audio ).
A quick Google search " Gas chromatography hydrogen isotopes " found plenty of relevant literature on separation techniques.
Please keep having fun,
Bruce Hamilton
