FLAME AAS AND UV-VIS DETERMINATION OF COBALT, NICKEL AND PALLADIUM USING THE SYNERGETIC EFFECT OF 2-BENZOYLPYRIDINE-2-PYRIDYLHYDRAZONE AND THIOCYANATE IONS

A quantitative synergetic extraction procedure for cobalt, nickel and palladium from thiocyanate aqueous solutions into methyl isobutyl keto ne (MIBK), containing 2-benzoylpyridine-2-pyridylhydrazone (BPPH), was studied by flame atomic absorption spectrometry (FAAS) and molecular absorption spectrometry (W-VIS). Using FAAS, linear calibration graphs were obtained from 0.0-0.5 mg l(-1) Co(II), 0.0-1.5 mg l(-1) Ni(II) a nd 0.0-2.0 mg l(-1) Pd(II). The reproducibilities were s(r, Co(II)) = 2.0%, s(r, Ni(II)) = 1.0% and s(r, Pd(II)) = 1.3% and the limits of de tection were c(L, Co(II)) = 0.004 mg l(-1), c(L,) (Ni(II)) = 0.009 mg l(-1) and c(L,) (Pd(II)) = 0.012 mg l(-1). Using UV-VIS method the lin ear calibration graphs were 0.0-0.5 mg l(-1) for Co(II), 0.0-1.0 mg l( -1) for Ni(II) and 0.0-2.0 mg l(-1) for Pd(II). The reproducibilities were s(r,) (Co(II)) = 1.3%, s(r,) (Ni(II)) = 1.7% and s(r,) (Pd(II)) = 1.0% and the limits of detection were c(L,) (Co(II)) = 0.001 mg l(-1) , c(L,) (Ni(II)) = 0.004 mg l(-1) and c(L,) (Pd(II)) = 0.002 mg l(-1). The extraction method is almost free from interferences and has been successfully applied to the determination of cobalt, nickel and pallad ium in dental alloys. (C) 1998 Elsevier Science B.V. All rights reserv ed.