%0 Journal Article
%T Surfactant Sensitized Calix[4]arenes Fluorescence Quenching Method for Speciation of Cr(VI)/Cr(III) in Water Samples
%A Wenjun Wang
%A Xiashi Zhu
%A Chaoguo Yan
%J ISRN Spectroscopy
%D 2013
%R 10.1155/2013/409480
%X The surfactant sensitized spectrofluorimetry for speciation of chromium (Cr(VI)/Cr(III)) was developed. The analytical procedure was that the fluorescence intensity of l4,10,16,22-tetramethoxyl resorcinarene carboxylic acid derivatives (TRCA) could be selectively quenched by Cr(VI) and the fluorescence quenching value ( ) was increased in cetyltrimethylammonium bromide (CTAB). The main influence factors on the fluorescence quenching (¦¤F) were investigated in detail. Under the optimal conditions, the linear range of calibration curve for the determination of Cr(VI) was 0.10~5.00£¿¦Ìg/mL, and the detection limit was 0.024£¿¦Ìg/mL with % ( £¿¦Ìg/mL, ). The concentration of Cr(III) was calculated by subtracting Cr(VI) from the total chromium determined after oxidizing Cr(III) to Cr(VI). The preliminary sensitized mechanism was discussed with the inclusion constant (K) of TRCA-Cr(VI), the fluorescence quantum yield of TRCA, and IR spectra characterization. The method has been applied to the speciation analysis of Cr(VI)/Cr(III) in water samples. 1. Introduction Chromium (Cr) is one of the most commonly present heavy metal pollutants in industrial wastewater. Chromium compounds mainly exist in two oxidation states(Cr(III) and Cr(VI)) in the environment. The reduced form of chromium Cr(III) is less toxic and is an essential nutrient required for normal glucose metabolism at low concentrations. Cr(VI) is much more mobile, toxic, and carcinogenic than Cr(III), which is widely used in electroplating, leather tanning, metal finishing, photography and dye and textile industries. The effluents from these industries often contain elevated levels of Cr(VI). Therefore, there is a great risk of chromium leaching from these effluents into the environment and our food chain. The World Health Organization (WHO) and the US Environmental Protection Agency (EPA) recommend that the concentration of Cr(VI) in drinking water should be less than 0.05£¿mg£¿L£¿1 and 0.1£¿mg£¿L£¿1, respectively [1¨C5]. Hence, the development of accurate and reliable methods for the speciation of Cr(III)/Cr(VI) in water samples is of particular significance to obtain comprehensive information about their toxicity and human health relevance. A variety of analytical methods such as ultraviolet visible absorption spectrometry (UV-Vis) [6], electrothermal atomic absorption spectrometry (ETAAS) [7], flame atomic absorption spectrometry (FAAS) [8¨C11], high performance liquid phase chromatography (HPLC) [12, 13], inductively coupled plasma mass spectrometry (ICP-MS) [14, 15], and gas chromatography (GC) [16] were
%U http://www.hindawi.com/journals/isrn.spectroscopy/2013/409480/