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 ketone (MIBK), containing 2-benzoylpyridine-2-pyridylhydrazone (BPPH), was studied by flame atomic absorption spectrometry (FAAS) and molecular absorption spectrometry (UV-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) and 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 detection 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 linear 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 palladium in dental alloys.