Precise Determination of the Atmospheric CF_4 Concentration by Using Natural Kr in the Atmosphere as an Internal Reference in the Preconcentration/GC/MS Analysis

摘要

For the precise determination of CF_4 in the atmosphere,the uniformly and constantly existing atmospheric krypton(Kr)was used as an internal reference because of its similar properties and behavior to CF_4 during the preconcentration processes and GC/ MS analysis.The precision of the concentration measurement normalized with a Kr isotope was remarkably improved(to less than 1%)and the sample amount necessary was largely reduced to about one tenth.