Determination of trace metals in size fractionated particles from arctic air by electrothermal vaporization inductively coupled plasma mass spectrometry

Abstract

Studies of element composition in small atmospheric particles aid the clarification of processes such as long-range transport, deposition and transformation of particles and quantification of emission from natural and anthropogenic sources. For this purpose, a highly sensitive method was developed for the trace analysis of atmospheric particles. The particles were sampled and separated according to size, directly on separate small graphite discs arranged behind the jet-nozzles of an eight-stage cascade impactor. To determine the elemental composition of the particles, the ETV-ICP-MS technique was applied. In an appropriately sealed electrothermal vaporizer, linked to an inductively coupled plasma mass spectrometer, the targets were heated and the sample vapour was swept by argon into the plasma. The system described was used for the analysis of long-range transported particles from Arctic air sampled at the German Arctic research station at Spitsbergen, Norway, in spring 1998. For the elements Mn, Fe, Co, Ni, Ag, Cd, Sn, Sb and Pb the trace element content per cubic metre of air was measured as a function of the aerodynamic particle diameter. Air masses of different origin cause characteristic particle distributions at low changes in total dust burden. The relative detection limits for the elements measured in an air volume of 0.275 m³ were determined to be within 0.3–10 pg m^–3; the overall analytical precision was around 20% for all trace metals.