The development of an analytical method for the determination of platinum (Pt) in environmental samples has been of concern in recent years because vehicles fitted with catalytic converters are spreading this element throughout the environment. A method for analysing low concentrations of Pt in roadside dust by dynamic reaction cell (DRC)-inductively coupled plasma mass spectrometry (ICP-MS), employing NH 3 reaction gas, is presented herein. The use of DRC technology permits the removal of the interfering species HfO 1 in Pt determination. The analysis of dust, collected by a modified vacuum cleaner at the roadside, employed digestion in a microwave oven by aqua regia, with subsequent filtration. The detection limit obtained was in the region of 8-10 ng g 21 for different Pt isotopes. The certified reference materials, NIST 2557 for auto catalyst and BCR 723 for road dust, were used to monitor the recovery of Pt in the method. Our results show that the conventional ICP-MS empirical corrections for such isobaric interferences of Pt may be inaccurate. Results are presented for Pt concentrations in road dust at various sampling locations in Hong Kong and these are highly correlated with vehicle traffic densities, but are not significantly correlated with the expected vehicle tracer species.

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Environmental Context.Sulfate in particulate matter is usually collected by a high-volume air sampler and analysed as a soluble extract by ion chromatography. The use of an inductively coupled plasma mass spectrometer fitted with a dynamic reaction cell enables not only the water-soluble, but also the total sulfate to be determined at the same time as the analyses of metal ions. Results from Hong Kong show that sulfate is strongly correlated with crustal species in particulate matter. Abstract.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 O2 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 32S16O+ determination is ~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 μm (PM10) in Hong Kong (n = 13) for soluble and total S were 5.2 ± 1.2 μg m–3 and 5.5 ± 1.3 μg 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.

Abstract. Five year (1995Five year ( -1999 datasets for inorganic major and trace components in PM 10 from three monitoring sites in Hong Kong are presented. The concentrations of most chemical constituents show a high degree of seasonality, with high concentrations in winter but low ones in summer, resulting from the combined effects of summer monsoon scavenging and the influx of the continental air mass of the winter monsoon. High correlations exist within crustal components, as well as within sea-salt components. Non-seasalt sulphate and ammonium ion contributions to the PM 10 mass are similar at all sites and are greatest in the winter months, showing the importance of non-local contributions. The concentrations of chemical components in PM 10 from this study are compared with those in wet deposition in Hong Kong, as well as with PM 10 results from other countries. In general, the Asian countries experience more elevated concentrations of PM 10 .