Electrothermal atomic absorption spectrometric determination of cobalt, copper, lead and nickel traces in aragonite following flotation and extraction separation

A method of determination of Co, Cu, Pb and Ni in nanogram quantities from aragonite is presented. Flotation and extraction of Co, Cu, Pb and Ni is suggested as methods for elimination matrix interferences of calcium. The method of flotation is performed by iron(III) hexamethylenedithiocarbamate, Fe(HMDTC)3, as a colloid precipitate collector. The liquid–liquid extraction of Co, Cu, Pb and Ni is carried out by sodium diethyldithiocarbamate, NaDDTC, as complexing reagent into methylisobutyl ketone, MIBK. The electrothermal atomic absorption spectrometry (ETAAS) is used for determination of analytes. The detection limits of ETAAS followed by flotation are: 7.8 ng·g−1 for Co, 17.1 ng·g−1 for Cu, 7.2 ng·g−1 for Pb and 9.0 μg·g−1 for Ni. The detection limits of ETAAS followed by extraction are found to be: 12.0 ng·g−1 for Co, 51.0 ng·g−1 for Cu, 24.0 ng·g−1 for Pb and 21.0 ng·g−1 for Ni.