AN AUTOMATED INSTRUMENT FOR THE ANALYSIS OF ATMOSPHERIC DIMETHYL SULFIDE AND CARBON-DISULFIDE

An automated gas chromatograph (GC) has been developed for the analysi s of the atmospheric concentrations of dimethyl sulfide (DMS) and carb on disulfide (CS2) at the Australian Baseline Air Pollution Station Ca pe Grim. The system comprises cryogenic concentration of DMS and CS2 f rom 4 1 of air after oxidant and water removal, capillary gas chromato graphy, and sulfur chemiluminescence detection. Calibration is by inje ction of a known quantity of methylethyl sulfide (MES) as an internal standard into the sampled air stream. Detection and quantitation of DM S and CS2 in the range of 5 to 500 ng/m(3), typical of the annual conc entration variation of DMS and CS2 at Cape Grim, has been achieved wit h 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 an d those obtained by a gold-coated glass wool trapping method with atom ic emission detection is presented.