Method for Determination of Impurities in Helium Gas.
U S Pat 3 691 818 Sept 19 1972 :
The helium content of a gaseous mixture is determined by comparing the partial pressure of the helium in an unknown sample directly with the pressure of high-purity helium under the same conditions. The volume percent of helium in the unknown is equal to (p1/p2) x 100, where p1 is the partial pressure of helium in the sample and p2 is the total pressure of an equal volume of high-purity helium. The partial pressure of the helium in the unknown sample is initially determined by adsorption of gases other than helium on activated charcoal at liquid nitrogen temperatures and measurement of the resulting helium pressure. The total pressure of high-purity helium is then measured under the same conditions as the sample.
U.S. Pat. 3,691,818, Sept. 19, 1972, Chem. Abstr. Not Found