Determination of trace levels of heavy metals in waters by extraction with ammonium tetramethylenedithiocarbamate and hexamethyleneammonium hexamethylenedithiocarbamate into xylene followed by inductively-coupled plasma emission spectrometry

The determination of Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V and Zn in river and sea water by inductively-coupled plasma emission spectrometry after extraction with a mixture of ammonium tetramethylenedithiocarbamate (APDC) and hexamethyleneammonium hexamethylenedithiocarbamate into xylene is described. All these elements are simultaneously concentrated 100-fold in a single extract and directly introduced into the plasma. The pH dependences of the extraction and the stabilities of the complexes are reported. The limits of detection of the method range from 0.017 ng ml^?1 (cadmium) to 0.5 ng ml^?1 (lead). With 100-fold concentration factors, calibration graphs are linear up to 30 ng ml^?1 or more.