Use of Diffusive Gradients in Thin Films to Predict Potentially Bioavailable Selenium in Soil

Abstract

In this study, diffusive gradients in thin films (DGT) were used for determination of anionic selenium (Se) species. First, a laboratory experiment was carried out to investigate ferrihydrite (the anionic sorbent in the DGT) complexation of anionic Se in an aqueous solution. A conditional DGT effective diffusion coefficient (D DGT ) for Se was estimated to be 5.0 Â 10 26 and 5.3 Â 10 26 cm 2 s 21 at pH 5.1 and pH 6.3, respectively. Second, DGT units were placed in pastes of soil that were sampled from a field experiment with mineral Se fertilization at two soil pH levels. Based on the DGT measurements, an effective concentration (C E ) for Se in soil was calculated. A C E (Se) value significantly higher than the control was estimated at the highest Se dose and the lower pH (5.5). Refinement of the method is needed, but this investigation indicates that the DGT technique can be used to determine potentially bioavailable Se fractions in soil.

Extending the functionality of the slurry ferrihydrite-DGT method: Performance evaluation for the measurement of vanadate, arsenate, antimonate and molybdate in water

“…S2). A previous study reported that the rate of mass accumulation of As V by SF-DGT decreased after 24 h, indicating a possible deterioration of sorption of the SF gels during deployment (Sogn et al, 2008).…”

“…Strong acids can digest and destroy the structure of the gels for complete release of elements from the binding layer. Previous studies showed that 0.25 M H2SO4 were used to elute SF gels for P V and concentrated HCl (Panther et al, 2008a, b) or HNO3 (Fitz et al, 2003;Sogn et al, 2008) for As V and Se VI . However, higher concentrations of acid used means greater dilutions steps are required for ICP-MS analysis, hence decreasing concentrations of target elements in samples and increasing the uncertainty of analysis, especially at lower concentrations.…”

Simultaneous measurements of As, Mo, Sb, V and W using a ferrihydrite diffusive gradients in thin films (DGT) device

“…Lately, reports of using the ferrihydrite-backed (FH) DGT for anion measurements have been published (e.g. [3][4][5][6]). The main uses have been phosphate [3] and inorganic arsenic [5] determinations, for which the FH DGT is now well-characterized.…”

“…A mixed binding layer DGT, holding both Chelex and ferrihydrite, has been used for molybdate and phosphate determination in soil along with simultaneous measurements of some cations [7]. Measurements have also been conducted for oxyanions of vanadium, molybdenum, antimony, tungsten and uranium in sediments [8,9] as well as selenium in soil [6].…”

Novel DGT method with tri-metal oxide adsorbent for in situ spatiotemporal flux measurement of fluoride in waters and sediments

“…the difference is more pronounced with a typical decrease in the range of 52-71% 315 depending on species Panther et al, 2008;Sogn et al, 2008 diffusive gels are well washed . …”