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In Situ Monitoring, Separation, and Characterization of Gold Nanorod Transformation during Seed-Mediated Synthesis



Thao M. Nguyen, John M. Pettibone, Julien Gigault, Vincent A. Hackley


Gold nanorods (GNRs) occupy a unique place in nanotechnology due to the ability to tune the optical properties from the middle visible to near IR spectrum by varying their size and aspect ratio (AR). Although there have been many anisotropic growth mechanisms proposed, rational design over the anisotropic shape transformation of metallic nanocrystals remains a fundamental challenge to the field. It has been well established that the nature and size of gold seeds strongly affect the yield, AR, and defect structures of GNRs in seed-mediated synthesis, but the seed-mediated approach yields a distribution of by-products that vary in shape and likely result from heterogeneity of the seed population itself. Furthermore, seed-mediated approaches do not result in predictable control over the shape, AR, or size of GNRs. A lack of validated analytical techniques to efficiently probe the different pathways for GNR formation from distinct seed populations, which would lead to rational design principles, has limited further progress in the field. In this study, we present an initial investigation of the synthesis and separation of gold nanomaterials using asymmetric-flow field flow fractionation (A4F) hyphenated with online UV-Vis and inductively coupled plasma-mass spectrometry (ICP-MS). Advantages afforded by tandem separation and characterization are an intrinsic capacity to provide rapid and accurate information over almost the entire distribution in the native environment of the analyte. With the coupling of A4F with UV-Vis and ICP-MS, a description of the physical properties of the transformation of gold nanoseeds to GNRs can be obtained, firmly establishing A4F as an indispensable technique for systematic studies of the mechanisms and key factors that contribute to the shape-shifting of gold nanoparticles to GNRs.
Analytical and Bioanalytical Chemistry


Field flow fractionation, gold nanorods, seed-mediated synthesis, transformation, hyphenated technique, inductively coupled plasma mass spectrometry


Nguyen, T. , Pettibone, J. , Gigault, J. and Hackley, V. (2016), In Situ Monitoring, Separation, and Characterization of Gold Nanorod Transformation during Seed-Mediated Synthesis, Analytical and Bioanalytical Chemistry, [online],, (Accessed April 18, 2024)
Created February 11, 2016, Updated October 12, 2021