Trace Level Arsenic Quantification through Methyl Red Bromination
- 1 Department of Studies in Chemistry, Bangalore University, Central College Campus, Bangalore, India
- 2 Department of Studies in Chemistry, Bangalore University, Central College Campus, Bangalore, India
Abstract
A simple protocol has been developed for the quantification of trace level arsenic through methyl red bromination. The proposed method is based on the oxidation of arsenic(III) to arsenic(V) by the bromine and the residual bromine’s reaction with methyl red to form colorless bromo methyl red. As the concentration of arsenic increases, the bleaching of the dye decreases due to bromine consumption. Measuring the intensity of the unreacted methyl red at 515 nm forms the basis of arsenic quantification. The molar absorptivity of this method has been found to be 2.25 × 103 L/mol/cm. The method obeys Beer’s law in the concentration range 0 - 0.25 μg/mL. The Sandell sensitivity and the limit of detection (LOD) were found to be 0.03 μg/mL/cm2 and 0.03 μg/mL respectively. The relative standard deviation has been found to be 0.35% at 1.0 μg/mL. The reaction conditions have been optimized and the interference due to various common cations and anions were studied. The proposed method has been successfully applied to the determination of trace level arsenic in various environmental samples like water, soil and vegetable samples.
- F. Colangelo, R. Cioffi, M. Lavorgna, L. Verdolotti, L. E. Munoz and S. P. Almero, “Analysis and Speciation of Arsenic by Stripping Potentiometry: A Review,” Talanta, Vol. 65, No. 3, 2005, pp. 613-620. doi:10.1016/j.talanta.2004.07.034
- B. K. Mandal and K. T. Suzuki, “Arsenic Round the World: A Review,” Talanta, Vol. 58, No. 1, 2002, pp. 201-235.
- B. Pesch, U. Ranft, P. Jakubis, M. J. Nieuwenhuijsen, M. Vega, L. Deban, R. Pardo and G. Gonzalez, “Determination of Copper and Arsenic in Refined Beet Sugar by Stripping Voltammetry without Sample Pretreatment,” Analyst, Vol. 123, No. 4, 1998, pp. 743-747.
- S. Gibaud, R. Alfonsi, P. Mutzanhardt, I. Fries and A. Astier, “(2-Phenyl-[1, 3, 2] dithio-arsolan-4-yl)-methanol Derivatives Show in Vitro Antileukemic Activity,” Journal of Organometallic Chemistry, Vol. 691, No. 5, 2006, pp. 1081-1084.
- X. Dai and R. G. Compton, “Detection of As(III) via Oxidation to As(V) Using Platinum Nano Particles Modified Glassy Carbon Electrodes: Arsenic Detection without Interference from Coppe,” Analyst, Vol. 131, No. 4, 2006, pp. 516-521. doi:10.1039/b513686e
- D. Das, A. Chatterjee, B. K. Mandal, G. Samanta, D. Charkroborty and B. Chanda, “Arsenic in Ground Water in Six Districts of West Bengal, India: The Biggest Arsenic Calamity in the World Part 2. Arsenic Concentration in Drinking Water, Hair, Nails, Urine, Skin-Scale and Liver Tissue (Biopsy) of the Affected People,” Analyst, Vol. 120, No. 3, 1995, pp. 917-924.
- P. L. Smedley and D. G. Kinniburgh, “A Review of the Source, Behavior and Distribution of Arsenic in Natural Waters,” Applied Geochemistry, Vol. 17, No. 5, 2002, pp. 517-568.
- K. Subrata, S. Kumar, M. Mandal, T. Pal and A. Pal, “Spectrophotometric Determination of Arsenic via Arsine Generation and in-Situ Colour Bleaching of Methylene Blue (MB) in Micellar Medium,” Talanta, Vol. 58, No. 5, 2002, pp. 935-942. doi:10.1016/S0039-9140(02)00434-4
- M. Burguera and J. L. Burguera, “Analytical Methodol- ogy for Speciation of Arsenic in Environmental and Biological Samples,” Talanta, Vol. 44, No. 9, 1997, pp. 1581- 1604. doi:10.1016/S0039-9140(97)00064-7
- R. K. Anderson, M. Thompson and E. Culbard, “Selective Reduction of Arsenic Species by Continuous Hydride Generation. Part I. Reaction Media,” Analyst, Vol. 111, No. 10, 1986, pp. 1143-1152. doi:10.1039/an9861101143
- C. T. Tye, S. J. Haswell, P. O. Neill and K. C. C. Bancroft, “High-Performance Liquid Chromatography with Hydride Generation/Atomic Absorption Spectrometry for the Determination of Arsenic Species with Application to some Water Samples,” Analytica Chimica Acta, Vol. 169, 1985, pp. 195-200.