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|Title:||Spectrophotometric determination of chromium using saccharin|
|Abstract:||A sensitive and selective spectrophotometric method for the indirect determination of trace amounts of chromium(VI) is described. Chromium(VI) oxidizes hydroxylamine in acetate buffer of pH 4.0 to nitrite, which then diazotizes p-nitroaniline or sulphanilamide to form diazonium salt. These diazonium salts are then coupled with saccharin in an alkaline medium, which gives azo dye with absorption maximum at 372 and 390 nm for p-nitroaniline and sulphanilamide, respectively. The method obeys Beer’s law in the concentration range of 1-16 gmL-1 for chromium with p-nitroaniline-saccharin and 0.6-14 gmL-1 of chromium with sulphanilamide-saccharin couples. The molar absorptivity, Sandell’s sensitivity of the systems with p-nitroaniline-saccharin and sulphanilamide-saccharin couples were found to be 5.41104 Lmol-1cm-1, 1.9310-3 gcm-2 and 2.63104 Lmol-1cm-1, 3.910-3 gcm-2, respectively. The optimum reaction conditions and other analytical parameters were evaluated. The effect of interfering ions on the determination was described. Chromium(III) can be determined after it is oxidized with bromine water in an alkaline medium to chromium(VI). The developed method has been successfully applied to the analysis of the chromium in alloy steel, pharmaceutical samples, natural water and soil samples.|
|ISSN:||0975-0991 (Online); 0971-457X (Print)|
|Appears in Collections:||IJCT Vol.12(5) [September 2005]|
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