Simultaneous spectrophotometric determination of chromium(VI) and iron(III) with chromogenic mixed reagents by H-point standard addition method and partial least squares regression
H. Abdollahi, Simultaneous spectrophotometric determination of chromium(VI) and iron(III) with chromogenic mixed reagents by H-point standard addition method and partial least squares regression, ANALYT CHIM, 442(2), 2001, pp. 327-336
Simultaneous determination of Cr(VI) and Fe(III) by partial least squares (
PLS) calibration and H-point standard addition method (HPSAM) is described.
Mixed reagents of diphenylcarbazide and 1,10-phenanthroline in a non-ionic
micellar solution of Triton X-100 was used as a selective chromogenic syst
em for determination of Cr(VI) and Fe(III). The presence of a micellar syst
em allows one to eliminate the previous solvent extraction step that is nec
essary for the determination of slightly soluble metal complexes in the abs
ence of micelles. This reduces the cost and toxicity of the method. The tot
al relative standard error for applying the PLS method to 15 synthetic samp
les in the ranges 0.20-6.00 mug ml(-1) Cr(VI) and 0.20-8.00 mug ml(-1) was
1.5%. The results of applying the H-point standard addition method showed t
hat Cr(VI) and Fe(III) can be determined simultaneously with weight concent
ration ratios of Cr(VI) to Fe(III) varying from 15:1 to 1:30 in the mixed s
ample. Both proposed methods (PLS and HPSAM) were also successfully applied
to the determination of Cr and Fe in several synthetic alloy solutions. (C
) 2001 Published by Elsevier Science B.V.