High-precision analysis of SF6 at ambient level

[摘要] This work reports on the development of a technique for the precise analysisof ambient SF₆. This technique, which involves a gaschromatograph/electron capture detector (GC-ECD) coupled with an ActivatedAlumina-F1 (AA-F1) column, performed well in the measurements, particularlyin terms of accuracy, which complies with the World MeteorologicalOrganization (WMO)-recommended compatibility of 0.02 ppt. Compared to thePorapak Q technique, we observed a sharper peak shape for the SF₆stream, which substantiates the improvement in the analytical precision. Thetraceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1analyser using five SF₆ standards provided by the WMO/Global AtmosphereWatch (GAW) Central Calibration Laboratory (CCL) for SF₆ (NOAA, UnitedStates of America). After calibration by various methods, the GC-ECD/AA-F1accurately estimated the mole fraction of SF₆ in the working standardprepared by the World Calibration Centre for SF₆ operated by the KoreaMeteorological Administration (KMA)/Korea Research Institute of Standards andScience (KRISS). Among the calibration methods, the two-point calibrationmethod emerged to be the most economical procedure in terms of the dataquality and measurement time. It was found that the KRISS scale ofSF₆/N₂ was biased by 0.13 ppt when compared to the WMO scale ofSF₆/air; this bias is probably due to a different matrix.

[学科分类] 几何与拓扑