Determination of ppb concentrations of transition metals by radioisotope-excited energy-dispersive X-ray spectrometry

Using ammonium pyrrolidine dithiocarbamate as precipitant and iron as a carrier, ppb concentrations of the following elements were coprecipitated from fresh water: vanadium, chromium, manganese, nickel, copper, zinc, selenium, mercury, and lead. Precipitates were collected on membrane filters then element concentrations were determined using energy dispersive X-ray fluorescence spectrometry. Calibration curves indicate sensitivities ranging from 0.4 ppb for V, Zn, As and Hg to 1.2 ppb for Pb. It is likely that this method of preconcentration can be directly incorporated into field sampling procedures, thus eliminating the problems of sample contamination or trace element losses by absorption on container walls.