Electrothermal atomisation atomic-absorption spectrometry with the direct introduction of slurries. Determination of trace metals in soil

Lead and cadmium are determined directly in soil by pipetting an aqueous slurry into a graphite furnace electrothermal atomiser. Aqueous calibration standards are used, and analyte recovery is complete provided that the soil is finely ground. The precision (relative standard deviation) at typical concentrations in soil is approximately 2–4% for cadmium and 8–9% for lead. The importance of soil particle size has been studied, and it is shown that insufficient grinding leads to poor recovery from larger particles. The major error is in the atomisation process, and analyte losses during pipetting of slurries into the atomiser are relatively small.