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Gold nanorod separation and characterization by asymmetric-flow field flow fractionation with UV-Vis detection



Julien C. Gigault, Tae Joon Cho, Robert I. MacCuspie, Vincent A. Hackley


The application of asymmetrical-flow field flow fractionation (A4F) for gold nanorod (GNR) fractionation and characterization was comprehensively investigated. We report on two novel aspects of this application. The first addresses the analytical challenge involved in the fractionation of positively charged nanoparticles by A4F, due to the interaction that exists between the negatively charged native membrane and the analyte. We show that the mobile phase composition is a critical parameter for controlling fractionation and mitigating the membrane-analyte interaction. A mixture of ammonium nitrate and cetyl trimethyl ammonium bromide at different molar ratios enables separation of GNRs with high recovery. The second aspect is the demonstration of shape-based separation of GNRs in A4F normal mode elution (i.e., Brownian mode). We show that the elution of GNRs is due both to aspect ratio and a steric-entropic contribution for GNRs with the same diameter. This latter effect can be explained by their orientation vector inside the A4F channel. Our experimental results demonstrate the relevance of the theory described by Beckett and Giddings for non-spherical fractionation1. However, it is shown that this theory has its limit in the case of complex GNR mixtures, and that shape (i.e., aspect ratio) is the principal material parameter controlling elution of GNRs in A4F; the apparent translational diffusion coefficient of GNRs increases with aspect ratio. Finally, the performance of the methodology developed in this work is evaluated by the fractionation and characterization of individual components from a mixture of GNR aspect ratios.
Analytical and Bioanalytical Chemistry


gold nanorod, nanoparticle, field flow fractionation, aspect ratio, hyphenation


Gigault, J. , Cho, T. , MacCuspie, R. and Hackley, V. (2012), Gold nanorod separation and characterization by asymmetric-flow field flow fractionation with UV-Vis detection, Analytical and Bioanalytical Chemistry, [online], (Accessed April 19, 2024)
Created November 14, 2012, Updated November 10, 2018