High-precision analysis of SF&amp;lt;sub&amp;gt;6&amp;lt;/sub&amp;gt; at ambient level

J S Lim,W.-T Yun,J S Kim,D M Moon,J Lee

doi:10.5194/amt-6-2293-2013

Abstract

Abstract. This work reports on the development of a technique for the precise analysis of ambient SF6. This technique, which involves a gas chromatograph/electron capture detector (GC-ECD) coupled with an Activated Alumina-F1 (AA-F1) column, performed well in the measurements, particularly in terms of accuracy, which complies with the World Meteorological Organization (WMO)-recommended compatibility of 0.02 ppt. Compared to the Porapak Q technique, we observed a sharper peak shape for the SF6 stream, which substantiates the improvement in the analytical precision. The traceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1 analyser using five SF6 standards provided by the WMO/Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for SF6 (NOAA, United States of America). After calibration by various methods, the GC-ECD/AA-F1 accurately estimated the mole fraction of SF6 in the working standard prepared by the World Calibration Centre for SF6 operated by the Korea Meteorological Administration (KMA)/Korea Research Institute of Standards and Science (KRISS). Among the calibration methods, the two-point calibration method emerged to be the most economical procedure in terms of the data quality and measurement time. It was found that the KRISS scale of SF6/N2 was biased by 0.13 ppt when compared to the WMO scale of SF6/air; this bias is probably due to a different matrix.

Highlights

Greenhouse gases (GHGs) in the atmosphere, which absorb and emit solar thermal energy, are known to be the prime cause of global warming
We describe the analysis of SF62usinFgiguare 1 ScFhiegm. 1a.tiSccdhieamgraamticodfiathgeraemxpoefritmheenetxalpeseritumpe.nUtaslinsgettuhpe.rUegsuinlagtothr ewriethgo-ut a gauge, gas chromatography-electron capture detector (GC-ECD) analyser coupled with an Activated Alu3mintah-eFu1nwanteudlactoorntwribituhtoiount aofggaausgees, mthoeourendwiannttheed dceoandtrviboulutimoen wofasgaesxepsecmteodortoedbe reduced
Where C is the mole fraction of SF6, R is the response area, and the subscripts stand for the references and the unknown sample

Summary

Introduction

Greenhouse gases (GHGs) in the atmosphere, which absorb and emit solar thermal energy, are known to be the prime cause of global warming. The observation of SF6 has become a vigorous activity under the GAW (Global Atmosphere Watch) Programme, which is suTpphoretedCbryy8o0scpouhnetrirees and up to 400 observatory sites worldwide. Lim et al.: High-precision analysis of SF6 at ambient level observation are located mostly on the European and American continents, according to the Global Atmosphere Watch. The establishment of a high-quality measurement system with reliable compatibility between the observation sites is regarded as a task of highest priority, taking into consideration the complications associated with the analytical results generated by a gas chromatography-electron capture detector (GC-ECD) system, which is the typical tool for the analysis of SF6. Detector, regardless of ambient pressure (Fig. 1). This configuration helped to get a reasonably steady response factor. 2 Experimental methods sity of an electron capture detector (μECD, Agilent 6890N), as a function of the retention time of analytes in the column

Analyser preparation and measurement capability

Preparation of working standard 5

High-precision analysis for SF66

Calibration methods

Summary and conclusion