SPECTROPHOTOMETRIC DETERMINATION OF IRON AND CHROMIUM IN CR-ELECTROPLATING BATHS AT THE HELWAN ENGINEERING INDUSTRIAL COMPANY USING PYROCATECHOL AS INDICATOR

The pyrocatechol (P.C.) was used as a selective spectrophotometric rea gent for Fe(III) and Cr(VI), under optimum conditions. The effects of pH and temperature on the spectra of iron-P.C. chelate and chromium-P. C. chelate were studied to select the optimum conditions for determina tion of iron(LII) and chromium(VI) in synthetic and in electroplating bath solutions. The suitable conditions for determination of Cr(VI) an d Fe(III) were 95 degrees C, and 25 degrees C at lambda(max) = 515 and 585 nm at the same pH = 5.0, respectively. The method succeeded for d etermination of Cr(VT) and Fe(III) with recovery 99.31-101.6%. The sta ndard deviation was found to be 0.98-1.6 which refered to the reproduc ibility and reliability of the applied procedures. The suggested proce dures using P,C. indicator were applied successfully for analysis of F e and Cr in 16 samples collected from the chromium-electroplating bath containing Fe(III) as contaminant. These procedures were also used fo r monitoring Fe(III) and Cr(VI) in the presence of each other during t he electroplating of steel utensils at the Helwan Engineering Industri al Company, Factory 99. (C) 1996 Academic Press, Inc.