The Use of Spectral Methods for the "Ensemble" Assessment of Synthesis Dynamics of the Arabinogalactan-Stabilized Selenium Nanoparticles.

Using spectral ensemble methods (DLS, optical and luminescence spectroscopy) and the transmission electron microscopy as reference method, the dynamics of selenium nanoparticles synthesis from sodium bis(2-phenylethyl)diselenophosphinate (DSePhNa) organophosphorus precursor in aqueous solution of polysaccharide matrix arabinogalactan (Ar-Gal) was studied. It was shown that the addition of hydrogen peroxide to the aqueous solution of DSePhNa initiates its oxidation with release of Se0 atoms with formation of selenium nanoparticles already by 10 s of synthesis. This stage identified by isolation of a fraction corresponding to nanoparticles in the size distribution. Full involvement of Ar-Gal macromolecules in the stabilization of formed selenium nanoparticles is completed by 8 min of the synthesis, which is accompanied by a narrowing of the size distribution of the formed nanoparticles. All basic stages of the particle formation and growth, as well as Ostwald ripening, in the case of long-term sample storage have been recorded by both TEM and the spectral ensemble methods. In the paper the most probable mechanism of selenium nanoparticle formation under the selected synthesis conditions is explained based on all the data obtained on the nature of nanoparticle size distribution. Besides, the possibility of using these spectral methods to estimate the dynamics of nanoparticle synthesis is discussed. Highlights: Spectral ensemble methods (DLS, optical and luminescence spectroscopy) can be used to evaluate the dynamics of nanoparticle synthesis in solution. The formation of nanoparticles is identified almost instantly (by 10 s of synthesis) by the separation of the small particle fraction, in the size distributions obtained from all spectral methods and confirmed by TEM. The nature (symmetry, modality) of the size distribution of Ar-Gal-stabilized SeNPs depends on the synthesis step and varies strongly over time until the completion stage of the process is reached. Prolonged storage of aqueous solution of Ar-Gal-stabilized SeNPs is characterized by non-stationary of state and is accompanied by a number of processes typical of Ostwald ripening leading also to changes in the character of disperse distribution of particles identified by all used spectral and TEM methods. [ABSTRACT FROM AUTHOR]