In situ, High-Resolution Measurement of Dissolved Sulfide Using Diffusive Gradients in Thin Films with Computer-Imaging Densitometry

Citations Over TimeTop 16% of 1999 papers

Abstract

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 Ag(2)S((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.

Related Papers

• → Corneal Densitometry as a Tool to Measure Epithelial Ingrowth After Laser In Situ Keratomileusis(2017)6 cited
• → A comparison between slit densitometry and video densitometry for quantitation in thin layer chromatography(2001)13 cited
• → Changes in distribution of bone densitometry equipment from 1996 to 2006 in Japan(2009)9 cited
• → Densitometry test of bone tissue: Validation of computer simulation studies(2008)7 cited
• Osteoporosis by forearm bone densitometry in postmenopausal women in West Virginia.(2007)