کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1163370 1490947 2015 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Influence of the settling of the resin beads on diffusion gradients in thin films measurements
ترجمه فارسی عنوان
تأثیر پراکندگی دانه های رزین بر شیب های پخش در اندازه گیری های فیلم های نازک
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
چکیده انگلیسی


• Influence of the inhomogeneous binding-agent distribution on DGT accumulations.
• Small mass decreases (<13%) can arise due to inhomogeneous Chelex distribution.
• A strategy for retrieving kinetic dissociation parameters is reported.

Binding resin beads used in DGT (diffusion gradients in thin films) tend to settle to one side of the resin during casting. This phenomenon might be relevant for metal accumulation when partially labile complexes dominate the metal speciation, especially after recognizing the important role played by complex dissociation in the resin domain. The influence of the inhomogeneity of the binding agent distribution on metal accumulation is here assessed by numerical simulation of DGT devices with binding beads in only one half of the resin disc, as a reasonable model of the standard resin discs. Results indicate that a decrease in mass accumulation of less than 13% can arise in these inhomogeneous devices (as compared with an ideal disc with homogeneous dispersion of the resin beads) when complexes with stability constant K < 102 m3 mol−1 (K < 105 L mol−1) dominate the metal speciation. The loss increases as K increases, but the percentage of mass loss always remains lower than the volume fraction of resin disc without beads. For very labile or inert complexes, the impact of the inhomogeneous distribution of binding resin beads is negligible. As kinetic dissociation constants of complexes can be estimated from the distribution of the metal accumulation in a DGT device with a stack of two resin discs, the influence of the inhomogeneity on the recovered kinetic constant is also assessed. For the cases studied, the recovered kinetic dissociation constant, kd,recovered, retains the correct order of magnitude, being related to the true kd by kd ≈ f−1 kd,recovered, quite independently of K and kd values, being f the fraction of volume of the resin disc where resin beads are dispersed.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Analytica Chimica Acta - Volume 885, 23 July 2015, Pages 148–155
نویسندگان
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