DETERMINATION OF COBALT, COPPER, LEAD AND NICKEL IN GYPSUM BY ZEEMAN ELECTROTHERMAL ATOMIC ABSORPTION SPECTROMETRY

Traje Stafilov and Dragica Zendelovska
Institute of Chemistry, Faculty of Science, Sts. Cyril and Methodius University,
POB 162, 91000 Skopje, Macedonia

ABSTRACT

A rapid method was developed for the extraction of cobalt, copper, lead and nickel from dissolved mineral samples by sodium diethildithiocarbamate into methylisobutyl ketone and their determination by Zeeman electrothermal atomic absorption spectrometry. The matrix interferences were investigated and results show that Ca (as matrix element) tends to decrease absorbance of investigated elements. Therefore, a separation of Co, Cu, Pb and Ni from the solution obtained by dissolution of gypsum in HCl was suggested. Standard addition technique was used for the evaluation of data and the method was tested using certified reference materials. The standard deviation (s) is 4 ngg-1 for Co, 17 ngg-1 for Cu, 8 ngg-1 for Pb and 7 ngg-1 for Ni. The detection limit of the method, calculated as 3s of the blank, was found to be 12 ngg-1 for Co, 51 ngg-1 for Cu, 24 ngg-1 for Pb and 21 ngg-1 for Ni.