Teasdale, Peter R. and Hayward, Sean and Davison, William (1999) In situ, high resolution measurement of dissolved sulfide using diffusive gradients in thin films with computer-imaging densitometry. Analytical Chemistry, 71 (11). pp. 2186-2191. ISSN 0003-2700Full text not available from this repository.
The technique of diffusive gradients in thin films (DGT) has been developed for the measurement of dissolved sulfide. Sulfide species from the sampled waters diffuse through a polyacrylamide hydrogel and then react with pale yellow AgI(s), incorporated at the surface of a second gel, to form black Ag2S(s). The accumulated sulfide can be measured with a conventional purge-and-trap method followed by colorimetry (methylene blue). This enables the dissolved-sulfide concentration to be calculated under suitable conditions. Alternatively, the color change in the accumulating gel can be used to measure sulfide. A conventional flat-bed scanner, allied to imaging software, provided a densitometric measurement that was quantitatively related to the amount of sulfide accumulated. DGT measurements on synthetic solutions accurately determined the sulfide concentration (95% recovery), thereby confirming the unobstructed diffusion of HS- through the gel. The accumulated mass was inversely proportional to the diffusion-layer thickness as theoretically predicted. With the selected geometry, the limit of detection of the densitometric procedure for a 24-h deployment was 0.13 μmol L-1, and the maximum concentration measurable was 60 μmol L-1. When used in anoxic lacustrine waters, DGT provided sensible concentrations. It was also used to measure depth profiles at submillimeter resolution in estuarine surface sediments.
|Journal or Publication Title:||Analytical Chemistry|
|Subjects:||G Geography. Anthropology. Recreation > GE Environmental Sciences|
|Departments:||Faculty of Arts & Social Sciences > Educational Research|
Faculty of Science and Technology > Lancaster Environment Centre
|Deposited On:||05 Feb 2009 14:27|
|Last Modified:||26 Jul 2012 15:51|
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