EC-28. A Third-Generation Electron Capture Gas Chromatograph System for the Analysis of Ozone-Depleting Chemical in Flask-Air Samples.

The HATS group of NOAA’s Global Monitoring Laboratory (GML) has been measuring chlorofluorocarbons (CFCs) and other ozone-depleting, trace-level gases collected in stainless steel and glass flasks from a global network of field sites since the late 1970s. The original system in use at the program’s inception was a gas chromatograph with electron capture detection (GC-ECD) for the measurement of CFC-11, CFC-12 and N2O. The HATS flask program has expanded greatly since then to measure many more trace gases at many more sites using a variety of gas chromatograph systems outfitted either with electron capture detectors or with mass selective detectors. Recently, our second-generation GC-ECD system was retired after 25 years in operational service. The poster will introduce its successor: a 3-channel GC-ECD system centered around an Agilent 7890b gas chromatograph for highly-precise and accurate measurements of CFC-11, CFC-12, CFC-113, CCl4, H-1211, CHCl3, N20 and SF6. We will describe some of the unique design features that differentiate this system from its immediate predecessor. We will also show some comparisons between results from this new system and other systems within GML.