Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 431360
Title Speciation analysis of aqueous nanoparticulate diclofenac complexes by solid-phase microextraction
Author(s) Zielinska, K.; Leeuwen, H.P. van; Thibault, S.; Town, R.M.
Source Langmuir 28 (2012)41. - ISSN 0743-7463 - p. 14672 - 14680.
DOI https://doi.org/10.1021/la303143w
Department(s) Physical Chemistry and Colloid Science
WIMEK
Publication type Refereed Article in a scientific journal
Publication year 2012
Keyword(s) bovine serum-albumin - walled carbon nanotubes - drug binding-sites - capillary-electrophoresis - aquatic environment - antiinflammatory drugs - mass-spectrometry - metal-complexes - water samples - nd-spme
Abstract The dynamic sorption of an organic compound by nanoparticles (NPs) is analyzed by solid-phase microextraction (SPME) for the example case of the pharmaceutical diclofenac in dispersions of impermeable (silica, SiO(2)) and permeable (bovine serum albumin, BSA) NPs. It is shown that only the protonated neutral form of diclofenac is accumulated in the solid phase, and hence this species governs the eventual partition equilibrium. On the other hand, the rate of the solid/water partition equilibration is enhanced in the presence of the sorbing nanoparticles of SiO(2) and BSA. This feature demonstrates that the NPs themselves do not enter the solid phase to any appreciable extent. The enhanced rate of attainment of equilibrium is due to a shuttle-type of contribution from the NP-species to the diffusive supply of diclofenac to the water/solid interface. For both types of nanoparticulate complexes, the rate constant for desorption (k(des)) of bound diclofenac was derived from the measured thermodynamic affinity constant and a diffusion-limited rate of adsorption. The computed k(des) values were found to be sufficiently high to render the NP-bound species labile on the effective time scale of SPME. In agreement with theoretical prediction, the experimental results are quantitatively described by fully labile behavior of the diclofenac/nanoparticle system and an ensuing accumulation rate controlled by the coupled diffusion of neutral, deprotonated, and NP-bound diclofenac species.
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