1、Designation:E 1772 95(Reapproved 2001)Standard Test Method forParticle Size Distribution of Chromatography Media byElectric Sensing Zone Technique1This standard is issued under the fixed designation E 1772;the number immediately following the designation indicates the year oforiginal adoption or,in
2、the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method is valuable for the measurement ofparticle size and covers determination
3、 of the particle sizedistribution of chromatography media in the overall size rangeof approximately 1 to 450 m using the electric sensing zone(ESZ)apparatus.This instrument uses an electric current pathof small dimensions that is modulated by individual particlepassage through an aperture and produc
4、es individual pulses ofamplitude proportional to the particle volume(1).21.2 The values stated in SI units are to be regarded as thestandard.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
5、establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water3E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods4E 456 Terminology Rela
6、ting to Quality and Statistics42.2Other Document:Manufacturers Operating Manual for Particle Size Distri-bution Analyzer53.Terminology3.1 Definitions:3.1.1 equivalent volume diameterthe diameter of a spherewith a volume equal to that of the actual particle.3.1.2 volume weighted(mass)median diametera
7、 numberdistribution,n(d),is measured,and N 5(i 5 1Cn(di)is thetotal number of particles in the C classes and n(di)is thenumber of particles in class i(corresponding to diameter di).3.1.2.1 DiscussionFrom n(d),the corresponding volumedistribution can be calculated:fdi!5 ndi!p6di3/V 5 ndi!di3/(i 5 1Cn
8、di!di3(1)where:V 5p6(i 5 1Cndi!di3(2)is the total particle volume.A cumulative volume distribution,F(di),is defined byFdi!5(xi#difxi!(3)The volume weighted(mass)median diameter is the diameter,d50,given byFdi!5 0.5(4)that is,the diameter that divides the particle volume into two equallysized halves.
9、4.Summary of Test Method4.1 A carefully dispersed,dilute suspension of the particlesin a beaker filled with electrolyte is placed in the countingposition on the instrument sample stand.The suspension isforced through a restricting aperture.Each particle passing isrecorded on an electronic counter ac
10、cording to selected particlesize levels.4.2 The instrument determines the particle volume(liquiddisplacement);therefore,the equivalent spherical diameter iscommonly used to express the particle size.5.Significance and Use5.1 It is important to recognize that the results obtained bythis test method o
11、r any other test method for particle sizedetermination using different physical principles may disagree.The results are strongly influenced by physical principles usedby each method of particle size analysis.The results of anyparticle sizing method should be used only in a relative senseand should n
12、ot be regarded as absolute when comparing resultsobtained by other methods.5.2 Both sellers and purchasers of chromatography mediawill find the test method useful if mutually acceptable to allparties concerned to determine the particle size distributionsfor materials specifications,manufacturing con
13、trol,and devel-opment and research.1This test method is under the jurisdiction of ASTM Committee E48 onBiotechnology and is the direct responsibility of Subcommittee E48.03 on UnitProcesses and Their Control.Current edition approved Nov.10,1995.Published January 1996.2The boldface numbers in parenth
14、eses refer to the list of references at the end ofthis test method.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 14.02.5Available from Coulter Corp.,Scientific Instruments,P.O.Box 169015,MC195-10,Miami,FL 33116-9015.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocke
15、n,PA 19428-2959,United States.6.Apparatus6.1 Electronic Particle Counter,using the ESZ technique,for example,Multisizer II from Coulter Electronics Ltd.,Elzone 280 from Particle Data Inc.,or their equivalent.6.1.1 The apertures are selectable from 50,70,100,140,280,400,and 560-m diameter.The measuri
16、ng range for eachsensor is approximately 2 to 80%of the aperture diameter(2).6.2 MicroscopeZeissAxioplan from Carl Zeiss,Germany,or similar microscope.6.3 Filtering DevicePeristalic pump with 0.22-m mem-brane filters(Sterivex-GS Millipore Corp.).6.4 Ultrasonic Bath,50 to 100 W and 60 to 80 kHz.7.Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reag
