ASTM WK68377

    New Test Method for Determination of the Mass Fraction of Particle-Bound Gold in Colloidal Gold Suspensions

    (What is a Work Item?)

    Developed by Subcommittee: E56.02 | Committee E56 | Contact Staff Manager



    WK68377

    1. Scope

    1.1 This test method describes the use of inductively coupled plasma optical emission spectrometry (ICP-OES; also includes ICP-AES, in which AES is atomic emission spectrometry) or inductively coupled plasma mass spectrometry (ICP-MS) for the determination of the mass fraction of particle-bound gold (Au) in colloidal Au suspensions. Particle-bound Au is defined as the mass of Au associated with the nanoparticle (NP) and adsorbed to the particle surface. The mass fraction of particle-bound Au is determined by subtracting the mass fraction of unbound Au measured in acidified subsamples of the particle-free supernatant from the Au mass fraction measured in acid-digested subsamples of the colloidal Au suspension. The particle free-supernatant is obtained after centrifugation of the colloidal Au suspension. This test merthod prescribes the use of an appropriate internal standard and calibration using either external standardization or standard additions. 1.2 Colloidal gold suspensions with AuNP diameters ranging from 1 to 100 nm can be determined with this test method. 1.3 No detailed instructions for operating instrumentation are provided because of differences among various makes and models. Instead, the analyst shall follow the instructions provided by the manufacturer of their particular ICP-OES, ICP-MS or centrifuge instrument, especially with regard to optimization of the instrument settings. 1.4 Units--The values stated in SI units are regarded as the standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices/controls and determine the applicability of regulatory limitations prior to use.


    Keywords

    Au; particle-bound Au; nanoparticles; colloidal suspension; optical emission spectrometry; mass spectrometry

    Rationale

    The unique optical, chemical, and electronic properties of gold nanoparticles (AuNPs) have led to their use in electronics, catalysis, and advanced coatings, but by far, the largest application has been for biomedical purposes, including imaging, diagnostics, photothermal therapy, and targeted drug delivery. To understand better their toxicity profile and behavior in vivo, characterization of the material properties of AuNP suspensions is required. This ballot addresses the need for methodology to determine the mass fraction of bound gold nanoparticles in suspension. The mass fraction of particle-bound Au is used in conjunction with AuNP size to compute AuNP number concentration, an important metric that will be a component of potential future regulation of nanomaterials. This proposed test method will be useful to nanomaterial producers, researchers, and regulators studying the efficacy and safety of gold nanomaterials.

    The title and scope are in draft form and are under development within this ASTM Committee.

    Citing ASTM Standards
    Back to Top
    Work Item Status

    Date Initiated:
    05-20-2019

    Technical Contact:
    Karen Murphy

    Item:
    001

    Ballot:
    E56 (20-05)

    Status:
    Ballot Item Approved as E3269-2021 and Pending Publication

    Item:
    001

    Ballot:
    E56 (20-04)

    Status:
    Ballot Item Approved as E3269-2021 and Pending Publication