+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

A systematic determination of diffusion coefficients of trace elements in open and restricted diffusive layers used by the diffusive gradients in a thin film technique

, : A systematic determination of diffusion coefficients of trace elements in open and restricted diffusive layers used by the diffusive gradients in a thin film technique. Analytica Chimica Acta 888: 146-154

A systematic comparison of the diffusion coefficients of cations (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) and oxyanions (Al, As, Mo, Sb, V, W) in open (ODL) and restricted (RDL) diffusive layers used by the DGT technique was undertaken. Diffusion coefficients were measured using both the diffusion cell (Dcell) method at pH 4.00 and the DGT time-series (D(DGT)) method at pH 4.01 and 7.04 (pH 8.30 was used instead of 7.04 for Al) using the Chelex-Metsorb mixed binding layer. The performance of Chelex-Metsorb as a new DGT binding layer for Al uptake was also evaluated for the first time. Reasonable agreement was observed between D(cell) and D(DGT) measurements for both ODL and RDL, except for V and W. The ratios of D(cell)/D(DGT) for V of 0.44 and 0.39, and for W of 0.66 and 0.63 with ODL and RDL respectively, were much lower due to the formation of a high proportion of polyoxometalate species at the higher concentrations required with the D(cell) measurements. This is the first time that D values have been reported for several oxyanions using RDL. Except for Al at pH 8.30 with ODL, all D(DGT) measurements were retarded relative to diffusion coefficients in water (DW) for both diffusive hydrogels. Diffusion in RDL was further retarded compared with ODL, for all elements (0.66-0.78) with both methods. However, the degree of retardation observed changed for cations and anions at each pH. At pH 7.04 cations had a slightly higher D(DGT) and oxyanions had a slightly lower D(DGT) than at pH 4.01 for both ODL and RDL. It is proposed that this is due to partial formation of acrylic acid functional groups (pKa ≈4.5), which would be fully deprotonated at pH 7.04 (negative) and mostly protonated at pH 4.01 (neutral). As Al changes from being cationic at pH 4.01 to anionic at pH 8.30 the results were more complex.


PMID: 26320970

DOI: 10.1016/j.aca.2015.07.027

Other references

Harcombe, W.R.; Bull, J.J., 2005: Impact of phages on two-species bacterial communities. A long history of experimental work has shown that addition of bacteriophages to a monoculture of bacteria leads to only a temporary depression of bacterial levels. Resistant bacteria usually become abundant, despite reduced growth rates relative...

Rosenblum, M.D.; Woodliff, J.E.; Madsen, N.A.; McOlash, L.J.; Keller, M.R.; Truitt, R.L., 2005: Characterization of CD 200-receptor expression in the murine epidermis. CD 200 is a widely expressed transmembrane glycoprotein that transmits an inhibitory signal after ligation of the structurally homologous CD 200-receptor-1 (CD 200 R1). Recently, we showed that CD 200 is expressed on keratinocytes and plays a role...

Fulop, T.; Douziech, N.; Desgeorges, S.; Goulet, A.C.; Linteau, A.; Bergevin, M.; Lacombe, G.; Arcand, M.; Dupuis, G., 2000: Apoptosis in T lymphocytes and polymorphonuclear leukocytes with aging. FASEB Journal 14(4): A194, March 15

Espinoza, B.; Wharton, W., 1986: Effects of cholera toxin and isobutylmethylxanthine on growth of human fibroblasts. Cholera toxin produced a dose-dependent decrease in the restimulation of G0/G1 traverse in density-arrested human fibroblasts but did not inhibit the stimulation of cells arrested in G0 after serum starvation at low density. In addition, cholera t...

Pullan S.E.; Good R.L.; Ricketts B.D., 1995: Preliminary results from a shallow seismic reflection survey, Lower Fraser Valley hydrogeology project, British Columbia. The results of the testing phase of a shallow seismic reflection survey carried out in 1994 as a component of the Lower Fraser Valley hydrogeology project are summarized in this paper. The quality of the seismic reflection data obtained varied wid...

Dunn, J.S.; McNee, J.W., 1917: A Contribution To The Study Of War Nephritis. British Medical Journal 2(2971): 745-751

Robie R.A.; Hemingway B.S.; Wilson W.H., 1978: Low-temperature heat capacities and entropies of feldspar glasses and of anorthite. American Mineralogist 63(1-2): 109-123

Pan, H-ping., 2005: Progress in studies of pharmacological activities and clinical applications of preparations of dried leaf of Ginkgo biloba. The progress in the research of the pharmacological activities and clinical applications of preparations of dried leaf of Ginkgo biloba is summarized. The preparations of G. biloba contain various chemical constituents, and have activities of rela...

Minami, T.; Miki, T.; Fujiwara, T.; Kawabata, S.; Izumitani, A.; Ooshima, T.; Sobue, S.; Hamada, S., 1989: Caries-inducing activity of isomaltooligosugar (IMOS) in in vitro and rat experiments. The caries-inducing activity of Isomaltooligosugar (IMOS: a isomaltose rich sugar mixture) was examined in in vitro and in vivo experiments. Strains of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 fermented IMOS and produced acids....

Rosen, M.P.; Sher, S.; Bhorade, R.; Patil, S.; Jacoby, H.; Davis, R.B.; Raptopoulos, V., 1999: Screening admission CT scans in patients with AIDS--a randomized trial. To determine if the length of hospital stay could be reduced for patients with AIDS by performing screening head and abdominal-pelvic computed tomography (CT) scans within 24 hours of admission, regardless of presenting signs and symptoms. Randomi...