Simultaneous determination of Cr(III) and Cr(VI) using differential pulse polarography and application to Gerede River

Authors : Olcay ŞENDİL, Nabeel MOHAMMED, Güler SOMER

Pages : 335-346

View : 10 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Determination of Crinsert ignore into journalissuearticles values(III); in the presence of Crinsert ignore into journalissuearticles values(VI); from one polarogram is not easy. No such procedure was found in the literature. In polarographic studies Crinsert ignore into journalissuearticles values(III); had a peak only in acidic medium, while Crinsert ignore into journalissuearticles values(VI); had either 1 or 2 peaks in both acidic and basic solutions. In solutions that contain these 2 ions, the peak obtained in acidic medium for Crinsert ignore into journalissuearticles values(III); will be the sum of both ions. Thus, Crinsert ignore into journalissuearticles values(III); cannot be determined directly from one polarogram. In this work, a new and simple polarographic method is established for the determination of Crinsert ignore into journalissuearticles values(III); and Crinsert ignore into journalissuearticles values(VI); by using only one polarogram. The most suitable electrolyte for this purpose was 0.1 M KNO3/HNO3 insert ignore into journalissuearticles values(pH 2-3);. The detection limits were 3 \times 10-7 M for Crinsert ignore into journalissuearticles values(III); and 1 \times 10-6 M for Crinsert ignore into journalissuearticles values(VI); in this medium. No interference was observed from most common ions. For validation, a sample containing both Crinsert ignore into journalissuearticles values(VI); and Crinsert ignore into journalissuearticles values(III); was analyzed also using 2 polarograms and good agreement was obtained. The proposed newly established direct method is applied to a real sample. For this purpose Gerede River in Turkey, which is surrounded by many leather factories, was analyzed for its chromium content, and agreement with ICP -- OES was very good.
Keywords : Chromium speciation, Cr VI, and Cr III, determination, differential pulse polarography, application to wastewater