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Size Determination of Aqueous C60 by Asymmetric Flow Field-Flow Fractionation (AF4) and in-Line Dynamic Light Scattering
Citation:
Isaacson, C., X. MA, B. Wigington, AND D. BOUCHARD. Size Determination of Aqueous C60 by Asymmetric Flow Field-Flow Fractionation (AF4) and in-Line Dynamic Light Scattering. Presented at SETAC Europe 19th Annual Meeting, Goteborg, SWEDEN, May 31 - June 04, 2009.
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Description:
To date, studies on the environmental behaviour of aggregated aqueous fullerene nanomaterials have used the entire size distribution of fullerene aggregates and do not distinguish between different aggregate size classes. This is a direct result of the lack of analytical methods for the size separation of aggregated fullerenes. Asymmetric flow field flow fractionation (AF4) is a separation technique which is able to separate particles from 1 nm to 100 µm in diameter based on differences in particle diffusion coefficients in aqueous media. Upon size-separation using AF4, C60 aggregates ranged in size from less than 40 nm to 450 nm (the filter cut-off). The size distribution was found to be contingent on the method of aggregate generation. The aggregate sizes were determined by dynamic light scattering and corroborated with electron microscopy. AF4 fractions were also analyzed for apparent surface charge and mass concentration. As the size of the C60 aggregates increased the absolute value of their zeta potential decreased. Mass determination of AF4 fractions showed 50% of the mass of the C60 aggregates had diameters between 140 and 250 nm.