FLAME ATOMIC-ABSORPTION SPECTROMETRIC INVESTIGATION AND DETERMINATIONOF COBALT AND COPPER USING ETHANOLAMINE AND TRIETHANOLAMINE AS CHEMICAL MODIFIERS

In the flame atomic absorption spectrometric investigation and determi nation of cobalt and copper, serious interfering effects were observed from berate and silicate on cobalt whereas berate, iron, indium and i ridium interfered on copper. Enhancement, depression and absence of in terferences sere observed fi;om a range of organic species on both cob alt and copper, All of these effects were attributed to chemical inter ferences as a result of their occurrence at different flame profiles t o various extents. Ethanolamine (EA) and triethanolamine (TEA) were fo und to be effective chemical modifiers for complete elimination of the interferences encountered from the foreign species studied separately or in combination on cobalt and copper, respectively. The role of EA and TEA in eliminating the interfering effects originates from the sol ution for TEA whereas EA exerts its effect at the base of the burner w here complexation with cobalt takes place by heating, In the reaction zone, an equilibrium for the decomposition of EA-Co or TEA-Cu species is established, yielding a consistent number of free cobalt and copper atoms, The excess amount of the modifier decomposes in the reaction z one, creating a reducing medium, which shifts the equilibrium in favou r of analyte atomization, A procedure is proposed for the determinatio n of cobalt or copper in some of their complexes.