ASTM E2490-09

This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:E2490–08 Designation: E 2490 – 09
Standard Guide for
Measurement of Particle Size Distribution of Nanomaterials
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in Suspension by Photon Correlation Spectroscopy (PCS)
This standard is issued under the fixed designation E 2490; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Thisguidedealswiththemeasurementofparticlesizedistributionofsuspendedparticles,whicharesolelyorpredominantly
sub-100 nm, using the photon correlation (PCS) technique. It does not provide a complete measurement methodology for any
specific nanomaterial, but provides a general overview and guide as to the methodology that should be followed for good practice,
along with potential pitfalls.
1.2 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 and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
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2.1 ASTM Standards:
E 177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E 691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E 1617 Practice for Reporting Particle Size Characterization Data
F 1877 Practice for Characterization of Particles
2.2 ISO Standards:
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ISO 13320-1 Particle Size Analysis—Laser Diffraction Methods—Part 1: General Principles
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ISO 14488 Particulate Materials—Sampling and Sample Splitting for the Determination of Particulate Properties
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ISO 13321 Particle Size Analysis—Photon Correlation Spectroscopy
3. Terminology
3.1 Definitions of Terms Specific to This Standard— Some of the definitions in 3.1 will differ slightly from those used within
other (non-particle sizing) standards (for example, repeatability, reproducibility). For the purposes of this Guide only, we utilize
the stated definitions, as they enable the isolation of possible errors or differences in the measurement to be assigned to
instrumental, dispersion or sampling variation.
3.1.1 correlation coeffıcient, n—measure of the correlation (or similarity/comparison) between 2 signals or a signal and itself
at another point in time.
3.1.1.1 Discussion—If there is perfect correlation (the signals are identical), then this takes the value 1.00; with no correlation
then the value is zero.
3.1.2 correlogram or correlation function, n—graphical representation of the correlation coefficient over time.
3.1.2.1 Discussion—This is typically an exponential decay.
3.1.3 cumulants analysis, n—mathematical fitting of the correlation function as a polynomial expansion that produces some
estimate of the width of the particle size distribution.
3.1.4 diffusion coeffıcient (self or collective), n—a measure of the Brownian motion movement of a particle(s) in a medium.
3.1.4.1 Discussion—After measurement, the value is be inputted into in the Stokes-Einstein equation (Eq 1, see 7.2.1.2 (4)).
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Diffusion coefficient units in photon correlation spectroscopy (PCS) measurements are typically µm /s.
3.1.5 Mie region, n—in this region (typically where the size of the particle is greater than half the wavelength of incident light),
the light scattering behavior is complex and can only be interpreted with a more rigorous and exact (and all-encompassing) theory.
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This guide is under the jurisdiction ofASTM Committee E56 on Nanotechnology and is the direct responsibility of Subcommittee E56.02 on Characterization: Physical,
Chemical, and Toxicological Properties.
Current edition approved Oct. 1, 2008. Published November 2008.
Current edition approved April 1, 2009. Published June 2009. Originally approved in 2008. Last previous edition in 2008 as E 2490–08.
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For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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E2490–09
3.1.5.1 Discussion—T
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