SIMULTANEOUS FIRST-DERIVATIVE SPECTROPHOTOMETRIC DETERMINATION OF IRON(III) AND MOLYBDENUM(VI) IN COBALT-CHROMIUM AND NICKEL-CHROMIUM ALLOYS

A method is proposed for the simultaneous determination of iron(III) a nd molybdenum(VI) by first-derivative spectrophotometry based on the a bsorption spectra of their complexes with morin in the presence of a c ationic surfactant. The zero-crossing measurement technique is found s utiable for the direct measurement of the first-derivative value at th e specified wavelengths. Iron(III) (0.9-1.5 mu g ml(-1)) and molybdenu m(VI) (0.3-4.2 mu g ml(-1)) in different ratios have been determined s imultaneously. A critical evaluation of the proposed method is perform ed by statistical analysis of the experimental data. The method was ap plied to determine iron and molybdenum in different alloys.