1、Designation:E286512Standard Guide forMeasurement of Electrophoretic Mobility and Zeta Potentialof Nanosized Biological Materials1This standard is issued under the fixed designation E2865;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revisio
2、n,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 mobility andzeta potential in systems containing biological material
3、 such asproteins,DNA,liposomes and other similar organic materialsthat possess particle sizes in the nanometer scale(100 nm).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
4、 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:2E1470 Test Method for Charac
5、terization of Proteins byElectrophoretic Mobility(Withdrawn 2014)3E2456 Terminology Relating to Nanotechnology2.2 ISO Standards:4ISO 13099-1 Colloidal systems Methods for zeta-potential determination Part 1:Electroacoustic andelectrokinetic phenomenaISO 13099-2 Colloidal systems Methods for zeta-pot
6、ential determination Part 2:Optical methodsISO 13321 Particle Size Analysis Photon CorrelationSpectroscopy3.Terminology3.1 DefinitionsDefinitions of nanotechnology terms canbe found in Terminology E2456.3.2 Definitions of Terms Specific to This Standard:3.2.1 Brownian motionis the random movement of
7、 par-ticles suspended in a fluid caused by external bombardment bydispersant atoms or molecules.3.2.2 dielectric constantthe relative permittivity of a ma-terial for a frequency of zero is known as its dielectric constant(or static relative permittivity).3.2.2.1 DiscussionTechnically,it is the ratio
8、 of the amountof electrical energy stored in a material by an applied voltage,relative to that stored in a vacuum.3.2.3 electrophoretic mobilitythe motion of dispersed par-ticles relative to a fluid under the influence of an electrical field(usually considered to be uniform).3.2.4 isoelectric pointp
9、oint of zero electrophoretic mobil-ity.3.2.5 mobilitysee electrophoretic mobility.3.2.6 redox reactiona chemical reaction in which atomshave their oxidation number(oxidation state)changed.3.2.7 stability the tendency for a dispersion to remain inthe same form for an appropriate timescale(for example
10、,theexperiment duration;on storage at 358K).3.2.7.1 Discussion In certain circumstances(for examplewater colloid flocculation)instability may be the desiredproperty.3.2.8 van der Waals forcesin broad terms the forcesbetween particles or molecules.3.2.8.1 DiscussionThese forces tend to be attractive
11、innature(because such attractions lead to reduced energy in thesystem)unless specific steps are undertaken to prevent thisattraction.3.2.9 zeta potentialthe potential difference between thedispersion medium and the stationary layer of fluid attached tothe dispersed particle.3.2.10 zwitterionica mole
12、cule with a positive and a nega-tive electrical charge.3.2.10.1 DiscussionAmino acids are the best known ex-amples of zwitterions.4.Summary of Practice4.1 IntroductionIt is not the intention of this guide tospend any significant time on the theory of zeta potential and1This guide is under the jurisd
13、iction of ASTM Committee E56 on Nanotech-nology and is the direct responsibility of Subcommittee E56.02 on Physical&Chemical Characterization.Current edition approved Jan.1,2012.Published June 2012.DOI:10.1520/E2865-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM
14、 Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from International Organization for Standardization(
15、ISO),1,ch.dela Voie-Creuse,CP 56,CH-1211 Geneva 20,Switzerland,http:/www.iso.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the routes by which a particle acquires charge within a system.Indeed it may be more appropriate to deal only
16、 with themovement or mobility of particles under an electrical fieldwhere conversion to zeta potential is not even attempted.Therelevant text books(for example,see Hunter(1)5)should beconsulted along with the more academic ISO references(ISO13099-1 and ISO 13099-2).The IUAPC report(2)is also veryuseful,albeit fairly theoretical,but it does contain a section(4.1.2)entitled How and under which conditions the electro-phoretic mobility can be converted into-potential.TheCorbett and Jack paper(3)cont
