In situ redox speciation analysis of chromium in water by diffusive gradients in thin films using a DE81 anion exchange membrane

TALANTA

卷:154

Article

Suarez, Carlos A.¹  de Simone, Thays V.¹  Menegario, Amauri A.^1,2  Rolisola, Ana M. C. M.¹  Luko, Karen S.¹  Gastmans, Didier¹  da Conceicao, Fabiano T.²  Kiang, Chang H.^1,2 

[1] UNESP Univ Estadual Paulista, Ctr Estudos Ambientais, Ave 24-A,1515, BR-13506900 Rio Claro, SP, Brazil

[2] UNESP Univ Estadual Paulista, Inst Geociencias & Ciencias Exatas, Ave 24-A,1515, BR-13506900 Rio Claro, SP, Brazil

关键词: Diffusive gradients;    Thin films;    Passive sampler;    Paper-based DGT;    DE81 membrane;    Chromium speciation;   

DOI  :  10.1016/j.talanta.2016.03.085

来源: Elsevier

【 摘 要 】

A method for the in situ redox speciation analysis of chromium in water by the diffusive gradients in thin films (DGT) technique using a DE81 anion exchange membrane was successfully developed. For the selective uptake of Cr(VI), a DGT device containing an anion exchange membrane DE81 (cellulose acetate chromatographic paper) was used (DE81-DGT), while selective uptake of Cr(III) was carried out using DGT devices containing the Chelex-100 resin (Chelex-100-DGT). A correlation coefficient of 0.993 was obtained for the linearity of the immersion curves (mass versus time) using DE81-DGT. The diffusion coefficient values for Cr(VI) through the agarose diffusive layer were equal to 4.89 +/- 0.5 x 10(-6) cm(2) s(-1) and 3.95 +/- 0.02 x 10(-6) cm(2) s(-1) (T=23 +/- 1 degrees C, I=0.03 mol L-1 NaNO3) were obtained by using diffusion cell and immersion curves, respectively. The retention of Cr(VI) by the DE81 membrane in a synthetic sample and river water was not affected by the pH over a wide range 4-9). Recoveries of Cr(VI) between 90% and 120% from solutions of ionic strength ranging from 0.01 to 0. 5 mol L-1 NaNO3 were achieved. Finally, the redox speciation analysis of Cr(III) and Cr(VI) in spiked river water and synthetic samples was performed with recoveries greater than 80% and 87% by using Chelex-100-DGT and DE81-DGT devices, respectively. Those results were in excellent agreement with the diphenylcarbazide spectrophotometric method. (c) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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