کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
581516 877844 2009 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Speciation of Cr(III) and Cr(VI) in environmental samples determined by selective separation and preconcentration on silica gel chemically modified with niobium(V) oxide
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بهداشت و امنیت شیمی
پیش نمایش صفحه اول مقاله
Speciation of Cr(III) and Cr(VI) in environmental samples determined by selective separation and preconcentration on silica gel chemically modified with niobium(V) oxide
چکیده انگلیسی
In this study a new method for chromium speciation in water using solid phase extraction coupled to a flow injection system and flame atomic absorption spectrometry was developed. The adsorption behavior of Cr(III) and Cr(VI) on Nb2O5-SiO2 allowed the selective separation of Cr(III) from Cr(VI) in the pH range of 6-9. Thus, a method for Cr(III) preconcentration and extraction using Nb2O5-SiO2 was developed. Total chromium was determined after the reduction of Cr(VI) to Cr(III) using sodium sulfite in acidic medium. The operational variables of the preconcentration and reduction procedures were optimized through full factorial and Doehlert designs. The limit of detection for Cr(III) was 0.34 μg L−1 and the precision was below 4.6%. Results for recovery tests using different environmental samples were between 90 and 105%. Certified reference materials (NIST 1640 and NIST 1643e) were analyzed in order to check the accuracy of the proposed method, and the results were in agreement with the certified values.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hazardous Materials - Volume 161, Issue 1, 15 January 2009, Pages 450-456
نویسندگان
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