|Title:||Simultaneous Determination of Iron(III) and Cobalt(II) with N-Phenylcinnamohydroxamic Acid (PCHA) and Thiocyanate and Determination of Iron(III) with PCHA and Azide by Solvent Extraction and Spectrophotometry|
|Publisher:||Addis Ababa University|
|Abstract:||Iron(III) and cobalt(II) have been found to react with thiocyanate in the presence of phenylcinnamohydroxamic acid to form pinkish red and blue colored complexes, respec-tively. Both the complexes were found to be quantitatively extractable into ethylacetate from 0.5-1.5 N hydrochloric acid solutions. The spectra of iron(III) and cobalt(II) complexes exhibited absorption maxima in the visible region at 495 and 625 nm 1820 1 mol-1cm-1, with molar absorptivities of 18000 and respectively. The coloured systems obeyed Beer's law in the concentration range of 0.2-3.9 ppm of iron and 2-41 ppm of cobalt. The composition of the complexes have been found to be 1:2:2 (Fe:SCN-:PCHA) and 1:4 (Co:SCN-). The effect of foreign ions and other experimental variables in the extraction and determination of iron(III) and cobalt (II) have been studied. On the basis of these studies simple, precise, sensitive, and highly selective methods have been developed for the determination of iron(III) and cobalt(II) and for the simultaneous determination of both metal ions by solvent extraction and spectrophotometry. The methods have been applied successfully for the determina-tion of iron and cobalt in steel and biosamples. Iron(III) was also found to react with azide in the presence of PCHA to produce an orange coloured complex having a composition of 1:2:2 (Fe:N3:PCHA). The complex was found to be stable and quantitatively extractable into ethylacetate from 0.1-0.9 M HC1 solutions allowing repro-ducible and reliable spectrophotometric determination of iron. The complex has maximum absorption at 447 nm with molar absorptivity of 7500 1 mol-1cm-1 and obeyed Beer's law in the range of 0.5-9 ppm of iron(III). From the study of the effect of foreign ions and several variables, the method was found to be highly selective and largely free from rigid control of experimental variables. The method was found to be effective by applying for the determination of iron in blood and steel samples. Thus, a new rapid, precise, sensitive and highly selective method for determina-tion of iron(III) with PCHA and azide has been developed.|
|Description:||A Thesis Presented to the School of Graduate Studies Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Master of Science in Chemistry|
|Appears in Collections:||Thesis - Chemistry|
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