Ultra trace detection of perfluorocarbon tracers in reservoir gases by adsorption/thermal desorption in combination with NICI-GC/MS.

A new method for the analysis of perfluorocarbon tracers (PFTs) in reservoir samples based on adsorption/thermal desorption in combination with NICI-GC/MS is presented. The tracer compounds were trapped in tubes filled with a carbon molecular sieve and in a two-step procedure thermally desorbed before they were analyzed with NICI-GC/MS. The chromatographic background noise, visible on GC/ECD-systems, due to compounds normally present in petroleum reservoir gases, could not be seen with NICI-GC/MS. Determination of the perfluorocarbons in reservoir gas samples confirmed the applicability of the method. Tracer concentrations as low as 42 femtoliter/liter were detected.