Speciation, Preconcentration and Determination of Inorganic Chromium Species in Spring, Drinking, and Waste Water Samples

Abstract: In general, chromium is existed in stable oxidation states, such as Cr(III) and Cr(VI) in the environment. While a certain amount of Cr(III) is required for human metabolism, Cr(VI) is known to have toxic and carcinogenic effects for all living species. Chromium compounds are widely used in different fields, such as electroplating, dyeing, photographic and textile industries. Owing to this reason, it and its compounds can easily interfere with the water resources. Because of differences in toxicity, it is important to develop a sensitive analytical method for the speciation, preconcentration and determination of chromium species in the water resources. In this work, speciation and preconcentration of Cr(III) and Cr(VI) were performed using Amberlite CG-120 resin before detection step by flame atomic absorption spectrometry. The experimental conditions for model solutions were optimized so that Cr(III) was adsorbed in a column while Cr(VI) was not. To perform this, some experimental parameters, such as pH, eluent’ type/concentration/flow rate, sample solution flow rate and adsorbent amount were optimized. Furthermore, Cr(VI) was reduced to Cr(III) to determine total chromium. Then, Cr(VI) was calculated by the differences between total chromium and Cr(III). The limit of detection (3 s) and preconcentration factor were found to be 0.3 μg L^–1and 600, respectively. This proposed method was successfully applied for the determination of inorganic chromium species in the different spring waters supplied from Isparta province (Eyüpler Village), Burdur province (Ağlasun County), the commercial drinking water samples purchased from local market in Burdur province, and the waste water supplied from Isparta province (Suleyman Demirel Organized Industrial Region) at Turkey. The accuracy of the method was successfully checked by certified reference material (TMDA-70.2 Ontario Lake water) at 95% confidence level.