Oxygen isotopic fractionation of O2 during adsorption and desorptionprocesses using molecular sieve at low temperatures

Abstract

Cryogenic trapping using molecular sieves is commonly used to collect O2 extracted from silicates for 17O/16O and 18O/16O analyses. However, gases which interfere with 17O/16O analysis, notably NF3, are also trapped and their removal is essential for accurate direct measurement of the 17O/16O ratio. It is also necessary to identify and quantify any isotopic fractionation associated with the use of cryogenic trapping using molecular sieves.