ASTM_E_2834_-_12.pdf

Designation:E283412Standard Guide forMeasurement of Particle Size Distribution of Nanomaterialsin Suspension by Nanoparticle Tracking Analysis(NTA)1This standard is issued under the fixed designation E2834;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide deals with the measurement of particle sizedistribution of suspended particles,from 10 nm to the onset ofsedimentation,sample dependent,using the nanoparticle track-ing analysis(NTA)technique.It does not provide a completemeasurement methodology for any specific nanomaterial,butprovides a general overview and guide as to the methodologythat should be followed for good practice,along with potentialpitfalls.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C322 Practice for Sampling Ceramic Whiteware ClaysE456 Terminology Relating to Quality and StatisticsE1617 Practice for Reporting Particle Size CharacterizationDataE2490 Guide for Measurement of Particle Size Distributionof Nanomaterials in Suspension by Photon CorrelationSpectroscopy(PCS)2.2 ISO Standards:3ISO 13320 Particle Size AnalysisLaser Diffraction Meth-odsISO 13321 Particle Size AnalysisPhoton CorrelationSpectroscopyISO 14488 Particulate MaterialsSampling And SampleSplitting for the Determination of Particulate PropertiesISO 22412 Particle Size AnalysisDynamic Light Scatter-ing(DLS)3.Terminology3.1 Definitions:3.1.1 diffusion coeffcient,na measure to characterize therate a particular molecule or particle moves in a particularmedium when driven by random thermal agitation(Brownianmotion).3.1.1.1 DiscussionAfter measurement,the value is to beinputted into the Stokes-Einstein equation(Eq 1,see7.2.1.2(3).Diffusion coefficient units in nanoparticle trackinganalysis(NTA)measurements are typically cm2/s,rather thanthe correct SI units of m2/s.3.1.2 repeatability,nin NTA and other particle sizingtechniques,this usually refers to a measure of the precision ofrepeated consecutive measurements on the same group ofparticles under identical conditions and is normally expressedas a relative standard deviation(RSD)or coefficient of varia-tion(CV).3.1.2.1 DiscussionThe repeatability value reflects the sta-bility(instrumental,but mainly the sample)of the system overtime.Changes in the sample could include dispersion,aggre-gation and settling.3.1.3 reproducibility,nin NTA and particle sizing thisusually refers to a measure of the deviation of the resultsobtained from the first aliquot to that obtained for the secondand further aliquots of the same bulk sample(and therefore issubject to the homogeneity or heterogeneity of the startingmaterial and the sampling method employed).Normally ex-pressed as a relative standard deviation(RSD)or coefficient ofvariation(CV).3.1.3.1 DiscussionIn a heterogenous and polydisperse(forexample,slurry)system,it is often the largest error whenrepeated samples are taken.Other definitions of reproducibilityalso address the variability among single test results gatheredfrom different laboratories when inter-laboratory testing isundertaken,or operator-to-operator,instrument-to-instrument,location-to-location,or even day-to-day.It is to be noted thatthe same group of particles can never be measured in such a1This guide is under the jurisdiction of ASTM Committee E56 on Nanotech-nology and is the direct responsibility of Subcommittee E56.02 on Characterization:Physical,Chemical,and Toxicological Properties.Current edition approved April 1,2012.Published May 2012.DOI:10.1520/E2834-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 system of tests and therefore reproducibility values maytypically be considerably in excess of repeatability values.3.1.4 robustness,na measure of the change of the requiredparameter with deliberate and systematic variations in any orall of the key parameters that influence it.3.1.4.1 DiscussionFor example,dispersion energy input(that is,ultrasound power and duration)almost certainly willaffect the reported r