ASTM_D_3862_-_13_2019.pdf

Designation:D386213(Reapproved 2019)Standard Test Method forRetention Characteristics of 0.2-m Membrane Filters Usedin Routine Filtration Procedures for the Evaluation ofMicrobiological Water Quality1This standard is issued under the fixed designation D3862;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 test method covers a procedure to test membranefilters for their ability to retain bacteria whose diameter is equalto or slightly larger than the 0.2-m pore size of the membranefilter.1.2 The procedures described are for the use of userlaboratories as differentiated from manufacturers laboratories.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent Water3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 Grams stain,na routine bacterial stain that dividesbacteria into two categories,depending on whether they can bedecolorized with acetone,alcohol,or aniline oil after stainingwith one of the rosaniline dyes such as crystal violet,methylviolet,or gentian violet and treating with iodine.Those thatresist decolorization remain blue or violet and are designatedGram-positive;those that are decolorized and take up the redcounterstain,such as neutral red,safranin,or dilute carbolfuchsin are termed Gram-negative.3.2.2 vacuum,nfor the procedure used,source of suctionthat can produce a reading of 500 to 600 mm Hg on a vacuumgage.4.Summary of Test Method4.1 This test method is based on the cultivation of organ-isms whose diameters are equal to or slightly larger than poresof the membrane filter to be tested and then filtering a specificaliquot containing organisms through the membrane followedby an examination of the filtrate after incubation for sterility.Asterile filtrate indicates complete retention of the organism andvalidates the ability of the membrane to retain bacteria equal toor slightly larger than the stated pore size.5.Significance and Use5.1 Microbiological water testing procedures using mem-brane filtration are based on the premise that all bacteria withina specific size range will be retained by the membrane filterused.If the membrane filter does not retain these bacteria,falsenegative results or lowered density estimates may occur thatcould have serious repercussions due to the presence ofunrecognized potential health hazards in the water being tested,especially in drinking water.5.1.1 This procedure as devised will enable the user to testeach membrane filter lot number for its ability to retain allbacterial equal to,or larger than,the stated membrane poresize.5.2 Since this membrane is often used to sterilize nonauto-clavable liquids,it is essential that the retention characteristicsof this membrane are stable.1This test method is under the jurisdiction of ASTM Committee D19 on Waterand is the direct responsibility of Subcommittee D19.08 on Membranes and IonExchange Materials.Current edition approved Nov.1,2019.Published December 2019.Originallyapproved in 1990.Last previous edition approved in 2013 as D3862 13.DOI:10.1520/D3862-13R19.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 6.Apparatus6.1 Membrane Filtration Units,six.6.2 Vacuum Source,with trap vessel.6.3 Filtering flasks,1-L,with vacuum tubing into which aglass tube and aY-tube have been incorporat