Spectrophotometric Determination of Copper(II) and Iron (III) with 2,4-Dihydroxy-5-Bromoacetophenone Thiosemicarbazone

摘要

2,4-Dihydroxy-5bromoacetophenone thiosemicarbazone (DHBAT) was synthesized and used as a spectrophotometric reagent for copper and iron. Cu (II) Fe(III) form yellow coloured complex at pH 6.0 and 4.0 and show maximu absorption at 420nm and 380nm respectively. Molar absorptivities for Cu(II)-DHBAT and Fe(III)-DHBAT are 0.145*10~4 lit/molcm and 0.6*10~4 lit/mol cm respectively. Cu(II)-DHBAT has 1:1 (M:L) stoichiometry while Fe(III)-DHBAT complex has 1:2 (M:L) stoichiometry. Beer's law is obeyed up to 12.7 ppm of Cu(II) ion and 9.41 ppm of Fe(III) ion. The reagent has been found to give satisfactory results for the analysis of copper in brass and iron in pharmaceutical preparation. Formation of the complex has also been supported from the IR spectral data.