  Oxygen, nitrogen and methane purification efficiencies for a common zirconium
getter are measured in 1050 Torr of xenon gas. Starting with impurity
concentrations near 10^{-6} g/g, the outlet impurity level is found to be less
than 120*10^{-12} g/g for O2 and less than 950*10^{-12} g/g for N2. For methane
we find residual contamination of the purified gas at concentrations varying
over three orders of magnitude, depending on the purifier temperature and the
gas flow rate. A slight reduction in the purifier's methane efficiency is
observed after 13 mg of this impurity has been absorbed, which we attribute to
partial exhaustion of the purifier's capacity for this species. We also find
that the purifier's ability to absorb N2 and methane can be extinguished long
before any decrease in O2 performance is observed, and slower flow rates should
be employed for xenon purification due to the cooling effect that the heavy gas
has on the getter.
