Work Item
ASTM WK85352
New Guide for Standard Guide for Measuring Intensity, Polydispersity, Size, Zeta Potential, Molecular Weight, and Concentration of Nanoparticles in Liquid Suspension Using Laser Amplified Detection/Power Spectrum Analysis (LAD/PSA) Technology
1. Scope
This technology (LAD/PSA) is available in three different platforms, which will be designated as Platforms A, B and C.
Platform A: This is a solid state probe configuration which serves as the optical bench in each of the platforms. It consists of an optical fiber coupler with a y-beam splitter which directs the scattered light signal back to a detector The sensing end of the probe can be immersed in a suspension, or positioned to measure one drop of sample on top of the sensing surface.
Platform B: The same probe is permanently mounted in a case positioned horizontally to detect the signal from the sample from either a disposable or reusable cuvette.
Platform C. Two probes are mounted at opposite sides of a permanent sample cell mounted in a case. Both size distribution and Zeta Potential can be measured in this configuration.
The laser beam measuring the scattered light from the sample of nanoparticles, in all three platforms, is partially reflected back to the detector, and the optical power of the laser is added to the scattered light signal to give the highest signal to noise ratio among all DLS technologies.
This combined, amplified optical signal is transformed into a frequency Power Spectrum which is then transformed into a size distribution. This methodology eliminates the need to have to choose among different algorithms applied to an ill-posed mathematical problem, depending on the shape of the distribution, to achieve a correct size analysis.
Keywords
Nanoparticles, Suspensions, Dynamic Light Scattering, Size Distribution, Zeta Potential
Rationale
There are currently three distinctly different Dynamic Light Scattering (DLS) technologies being widely used in quality control and research to measure size and Zeta Potential of nanoparticles, which is a rapidly growing field in many new and existing application areas. The generally accepted size range of nanoparticles is 0 to 100 nanometers, but these technologies are usually capable of measuring up to 10 micrometers in some applications. Two of these technologies, Photon Correlation Spectroscopy (PCS), also known as Quasi-Elastic Light Scattering (QLS), and Nanotracking (NT) already have ASTM Standards addressing them, either as Guides or Test Methods. All three of these technologies have their own set of different benefits. With the addition of this Standard, all three will be represented in ASTM Standards.
The title and scope are in draft form and are under development within this ASTM Committee.
Work Item Status
Date Initiated: 02-17-2023
Technical Contact: Terry Stauffer
Item: 000
Ballot:
Status: