Kinetic Spectrophotometric Determination of Chromium (VI) by Oxidation of Sodium Pyrogallol-5-sulphonate by Hydrogen Peroxide |
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Authors: | Email author" target="_blank">Snezana S?MiticEmail author Gordana Z?Miletic Aleksandra N?Pavlovic Snezana B?Tosic |
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Institution: | (1) Faculty of Sciences and Mathematics, Department of Chemistry, University of Nis, P.O. Box 224, YU-18000 Nis, Serbia and Montenegro |
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Abstract: | Summary. A new selective, sensitive, and simple kinetic method is developed for the determination of trace amounts of chromium (VI). The method is based on the catalytic effect of Cr(VI) on the reaction of sodium pyrogallol-5-sulphonate (PS) with hydrogen peroxide. The reaction is followed spectrophotometrically by tracing the oxidation product at 437nm within 1min after addition of H2O2. The optimum reaction conditions are PS (1.32·10–3mol·dm–3), H2O2 (0.32mol·dm–3), HClO4 (2.6·10–3mol·dm–3) at 25°C. Following this procedure, chromium (VI) can be determined with a linear calibration graph up to 0.25ng·cm–3 and a detection limit of 0.024ng·cm–3, based on the 3 criterion. The interference effect of several species was also investigated and it was found that the most common cations and anions do not interfere with the determination. The developed procedure was successfully applied to the determination of Cr(VI) and total Cr in river waters and total Cr in herbal samples. |
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Keywords: | , Chromium determination, Kinetic spectrophotometric method, Sodium pyrogallol-5-sulphonate oxidation, |
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