* Corresponding Author
EXTRACTION AND SPECIATION OF CHROMIUM(VI) AND CHROMIUM(III) AS ION-ASSOCIATION COMPLEXES OF TETRAMETHYLAMMONIUM-CHROMATE
https://doi.org/10.22146/ijc.21751 Valencia Widiyaningrum Wandoyo(1*), Mudasir Mudasir(2), Roto Roto(3)
(1) Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO. Box BLS 21 Yogyakarta 55281
(2) Chemistry Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta 55281
(3) Chemistry Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta 55281
(*) Corresponding Author
Abstract
A specific, selective and simple method for speciation of chromium(VI) and chromium(III) has been developed. This method is based on the quantitative extraction of chromium(VI) and chromium(III) as an ion association of tetramethylammonium-chromate in methyl isobutyl ketone (MIBK), followed by back extraction and preconcentration with an acidic diphenylcarbazide (DPC) solution. Back extraction was applied to achieve further preconcentration by a final factor of 20. The chromium(VI)-DPC complex was determined by a UV-Visible spectrophotometer. The optimum conditions of this method are as follows, optimum wavelength at 545 nm, MIBK as organic solvent, 7.5 mL of nitric acid (65%) for each 100 mL sample, mole ratio of TMAC to Cr(VI) of 2x104:1, 5 min shaking time, mole ratio of DPC to chromium(VI) of 8:1, and immediate UV-Vis measurement after obtaining of back-extract. The calibration curve was linear in the concentration range 0.00-0.40 µg.mL-1 of chromium(VI) with a regression equation of Abs=0.0038+1.7427x, in which x was the chromium species concentration ( µg.mL-1). The correlation coefficient (r) for the curve was 0.9991 and the detection limit was found to be 0.946 µg.mL-1. The result of analysis and speciation of chromium in water samples from a river near a leather processing plant in Yogyakarta area showed that the total content of chromium was in the range of 0.04 - 0.05 µg.mL-1 consisting of 0.03 - 0.04 µg.mL-1 of chromium(VI) and 0.002 - 0.01 µg.mL-1 of chromium(III). This result indicates that the concentration of chromium in the river is still below the safety limit.
Keywords
Full Text:
Full Text PdfReferences
[1] Baig, M.A., Mehmood, B., and Matin, A., 2003, EJEAFChe, 2, 3.
[2] Bernard, 1997, Overview of Epidemiological Studies on The Carcinogenecity of Metals. In J. H. Duffus, Carcinogenicity of Inorganic Subtances: Risk from Occupational Exposure, The Royal Society of Chemistry, Cambridge, 149.
[3] Ouejhani, M. Dachraoui, G. Lalleve, and J. F. Fauvarque, 2003, Anal. Sci., 19, 1499.
[4] Underwood, E. J., 1997, Trace Elements in Human and Animal Nutritions, 4th ed., Academic Press, New York.
[5] Quevauviller, P., 1998, Method Performance Studies for Speciation Analysis, The Royal Society of Chemistry, Cambridge.
[6] De Jong J. H., and Brikman, U. A., 1978 J. Anal. Chem. Acta, 98, 243-250.
[7] Yotsuyanagi, T., Takeda, Y., Yamashita, R., and Aomura, K., 1973, Anal. Chim. Acta, 67, 297.
[8] Noroozifar, M., and Khorasani-Motlagh, M., 2002, Anal. Sci., 19, 705-708.
[9] Bubnis, P., Straka, M.R., and Pacey, G.E., 1983, Talanta, 30, 841.
[10] Marchart, H., 1964, J. Anal. Chem. Acta, 30, 11-16.
[11] Sandell, E.B., and Onishi, H., 1978, Photometric Determination of Traces of Metals, 4th ed., John Wiley & Sons, New York, 390.
[12] Svehla, G., 1987, Vogel’s Qualitative Inorganic Analysis, 6th ed., Longman Scientific & Technical, London, 115.
[13] Miller J.C., and Miller, J.N., 2000, Statistic and Chemometric for Analytical Chemistry, 4th ed., Pearson Education Limited, Harlow.
DOI: https://doi.org/10.22146/ijc.21751
Article Metrics
Abstract views : 2302
| 
views : 2698
Copyright (c) 2010 Indonesian Journal of Chemistry
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Indonesian Journal of Chemistry (ISSN 1411-9420 /e-ISSN 2460-1578) - Chemistry Department, Universitas Gadjah Mada, Indonesia.