Simultaneous sampling of phosphate, arsenate, and selenate in water by Diffusive Gradients in Thin Films (DGT)

Abstract

The DGT sampler was studied for simultaneous collection of phosphate, arsenate, and selenate in water. The DGT-based diffusion coefficients found were somewhat lower than the theoretical ones for free diffusion in water, but similar to what has been found earlier for phosphate and arsenate in diffusion cell experiments with the DGT membrane. Our results indicate that D sampler with the ferrihydrite adsorbent functions adequately as an adsorbent for phosphate, arsenate, and selenate in water, and may thus be used for simultaneous sampling of these three ions in water. The good performance for arsenate fills a gap in the DGT toolbox for passive sampling of high-priority trace elements, while it for selenate may prove very useful for assessing the potential for Se deficiency or toxicity in soil water.