Adventures in nanoparticle Metrology:
Preliminary Results on the Affinity of Gold Nanoparticles to Functionalized Silica Gel
Janelle Dawn Secl Newman, and William A. MacCrehan
Affiliation: CSTL/Analytical Chemistry Division, NIST Gaithersburg , MD 20899
Bldg. 227/B152, MS 8392, x3115, fax: 301-977-0685
Understanding the affinity between different types of stabilized gold nanoparticles (AuNPs) and chemical functional groups is important in understanding the fate of AuNPs in biological and environmental systems. The interactions between the stabilizing groups on the AuNPs and the chemical moieties they come into contact with can impact the colloidal aggregation and stability as well as influence the persistence of the particles within the system of interest.
We discuss here preliminary results on a study examining the interaction between aqueous colloids of citrate-stabilized, aniline-stabilized, and 4-methylaniline-stabilized AuNPs with silica gels functionalized with alkane (C18), carboxylic acid, primary amine, thiocyanate, and thiol functional groups. The colloids were exposed to the functionalized silica gels using simple column chromatography. The eluent was collected and evaporated to dryness for gravimetric breakthrough analysis. Additionally, the eluents were also examined using ultraviolet-visible spectroscopy. The silica gel was examined using colorimetric analysis of photographs in order to examine the extent of AuNP adsorption to the gel after exposure. The preliminary results of colloid breakthrough studies, post-interaction silica gel colorimetric analysis, and spectroscopy studies will be shown.