Water-soluble and total sulfur in particulate matter determined by inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS)

An instrumental method has been developed for the determination of sulfur in particulate matter using inductively coupled plasma dynamic reaction cell mass spectrometry. The reaction gas O-2 was employed to convert S+ into the diatomic species SO+, and analysed at two different mass-to-charge ratios. The limit of detection for the (SO+)-S-32-O-16 determination is similar to 1 ng S m(-3). The method has the advantages that not only soluble sulfur (as commonly analysed by ion chromatography) but also total sulfur can be determined on the same instrument as many metal species. The mean values ( standard deviations) for a spring sampling program of particulate matter of diameter less than 10 mu m (PM10) in Hong Kong (n = 13) for soluble and total S were 5.2 +/- 1.2 mu g m(-3) and 5.5 +/- 1.3 mu g m(-3) respectively. These values are quite low owing to a predominantly easterly airstream. Sulfur in PM10 is strongly correlated with the crustal species Ca, Al and Mn.