Wagner, A. T. and Kohler, H. -H. (2008) Determination of the concentration dependence of polyelectrolyte diffusion coefficients by application of the Boltzmann gradient method. JOURNAL OF COLLOID AND INTERFACE SCIENCE, 319 (2). pp. 555-564. ISSN 0021-9797,
Full text not available from this repository. (Request a copy)Abstract
The concentration dependence of a polyelectrolyte diffusion coefficient in aqueous low salt solution (KCl, 1 mM) is determined from a single dynamic gradient experiment. The Boltzmann method is applied to calculate the diffusion coefficient. A special diffusion cell is constructed that minimizes aberrations in the optical detection of the polyion concentration profile. Bovine serum albumin (BSA) is chosen as a model polyion. To get information about the diffusion process down to very small polyion concentrations, the BSA molecule is fluorescently labeled. The fluorescence intensity is used as a measure of the polyion concentration. The change of the polyion net charge caused by labeling is discussed. The cell is illuminated by an LED, and the fluorescence intensity profile is detected by a CCD camera. Experiments at 5 and 17 degrees C show that the diffusion coefficient of labeled BSA remains constant in the very low polyion concentration range below a threshold of about 1.5 g/l. This is in contradiction to the linear concentration dependence of polyion diffusion coefficients at very low concentrations often postulated in the literature without reference to direct experimental evidence. Our finding is confirmed by dynamic light scattering experiments published recently. An explanation for this behavior based on a modified Donnan osmotic compressibility approach is given. (C) 2007 Elsevier Inc. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | BOVINE SERUM-ALBUMIN; IONIC-STRENGTH; SEDIMENTATION; PROTEINS; polyion diffusion coefficient; concentration dependence of the diffusion coefficient; BSA; effective net charge; fluorescence label; Boltzmann gradient method; diffusion cell |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 05 Nov 2020 11:13 |
| Last Modified: | 05 Nov 2020 11:13 |
| URI: | https://pred.uni-regensburg.de/id/eprint/31177 |
Actions (login required)
 |
View Item |
