A new procedure has been developed which combines the advantages of two existing analytical methods. A preconcentration of the impurities as previously described by Kirkland, et al. (4) followed by analysis with a high-sensitivity gas chromatograph as reported by Purer and Seitz (7), resulted in an analytical procedure which has sensitivities in the parts-per-billion (ppb) range for neon, hydrogen, argon, oxygen, krypton, nitrogen, methane, and xenon.