An automated instrument for the analysis of atmospheric dimethyl sulfide and carbon disulfide

An automated gas Chromatograph (GC) has been developed for the analysis of the atmospheric concentrations of dimethyl sulfide (DMS) and carbon disulfide (CS2) at the Australian Baseline Air Pollution Station Cape Grim. The system comprises cryogenic concentration of DMS and CS2 from 4 I of air after oxidant and water removal, capillary gas chromatography, and sulfur chemiluminescence detection. Calibtation is by injection of a known quantity of methylethyl sulfide (MES) as an internal standard into the sampled air stream. Detection and quantitation of DMS and CS2 in the range of 5 to 500 ng/m3, typical of the annual concentration variation of DMS and CS2 at Cape Grim, has been achieved with a sampling frequency of 2 samples per hour and a detection limit of 10 pg S per compound. A comparison of results from the automated GC and those obtained by a gold-coated glass wool trapping method with atomic emission detection is presented.