Determination of copper, lead, cadmium, nickel and cobalt in EDTA extracts of soil by solvent extraction and graphite furnace atomic-absorption spectrophotometry

Abstract

A procedure is described for the determination of copper, lead, cadmium, nickel and cobalt in EDTA extracts of soil and similar material. Diethylammonium diethyldithiocarbamate or ammonium tetramethylene dithiocarbamate metal complexes are extracted into xylene from the EDTA extracts, and metals are determined in the xylene phase by atomic-absorption spectrophotometry using a graphite furnace atomiser. The detection limits (concentrations in soil) are approximately copper 0.8, lead 0.3, cadmium 0.07, nickel 2.5 and cobalt 0.8 µg g–1. These detection limits might be improved by at least a factor of 10. Iron, manganese, aluminium, calcium and zinc do not interfere in amounts likely to be found in extracts of natural or contaminated soils.