PRECONCENTRATION METHOD FOR ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRIC ANALYSIS FOR HEAVY-METALS IN ANTARCTIC SNOW AT SUB NG KG-1 LEVELS

An improved technique for concentrating heavy metals onto the surface of tungsten wires, prior to analysis by electrothermal atomic absorpti on spectrometry, is reported. Ultraclean methods and materials, descri bed here, have enabled improvements in detection limits to be realised . With the new procedure, detection limits of 0.01 ng Cd kg-1, 0.47 ng Cu kg-1, 0.22 ng Pb kg-1 and 0.24 ng Zn kg-1 are obtained. These are low enough to allow analysis of ancient and modern Antarctic snow, exc ept perhaps for cadmium. A comparison with samples injected directly i nto the graphite furnace shows good agreement, confirming that the met hod is suitable for the simple polar snow matrix.