Determination of trace amounts of nickel and cobalt in silicate rocks by graphite furnace atomic absorption spectrometry: elimination of matrix effects with an ammonium fluoride modifier

Abstract

Trace amounts of nickel and cobalt have been determined in a variety of standard rocks by graphite furnace atomic absorption spectrometry after fusion with a mixture of lithium carbonate and boric acid. The presence of ammonium fluoride in the reaction medium served to remove severe matrix effects, allowing aqueous hydrochloric acid solutions to be used as calibration standards. Results are given for a variety of standard rock samples. The sensitivities are 14 and 25 pg for nickel and cobalt, respectively, with respect to 1% atomic absorption.