1、Designation:D386387(Reapproved 2011)Standard Test Method forRetention Characteristics of 0.40 to 0.45-m MembraneFilters Used in Routine Filtration Procedures for theEvaluation of Microbiological Water Quality1This standard is issued under the fixed designation D3863;the number immediately following
2、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 pro
3、cedure to test membranefilters for their ability to retain bacteria whose diameter is equalto or slightly larger than membrane filters with pore size ratedat 0.40 to 0.45 m.1.2 The procedures described are for the use of userlaboratories as differentiated from manufacturers laboratories.1.3 This sta
4、ndard 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
5、 Standards:2D1129 Terminology Relating to WaterD1193 Specification for Reagent Water3.Terminology3.1 DefinitionsFor definitions of terms used in thismethod refer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 Grams staina routine bacterial stain that dividesbacteria in
6、to 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-
7、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 vacuumfor the procedure used,a source of suctionthat can produce a reading of 500 to 600 mm Hg on a vacuumgage.4.Summary of Test Method4.1 This test
8、 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.Aste
9、rile 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
10、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
11、water being tested,especially in drinking water.5.2 This procedure as devised will enable the user to testeach membrane filter lot number for its ability to retain allbacteria equal to,or larger than,the stated membrane pore size.6.Apparatus6.1 Membrane Filtration Units,six.6.2 Vacuum Source with tr
12、ap vessel.6.3 Filtering Flasks,1-L,with vacuum tubing into which aglass tube and aY-tube have been incorporated as in Fig.1.Thefree end of the Y-tube is connected by tubing to a sterilebacterial air vent.The tubing to air vent is clamped shut duringfiltration and released after filtration.6.4 Forcep
13、s,blunt-nosed,and small beaker of 95%ethanol.6.5 Incubator,20 to 25C.6.6 Pinch-Cock Clamps.6.7 Autoclave or Other Sterilizing Equipment.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 Mater
14、ials.Current edition approved May 1,2011.Published June 2011.Originallyapproved in 1987.Last previous edition approved in 2003 as D3863 87(2003).DOI:10.1520/D3863-87R11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Bo
15、ok 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 States1 6.8 Appropriate Equipment for producing reagent gradewater.6.9 Appropriate Laboratory G
16、lassware.6.10 Sterile Rubber Stoppers,to fit 1-L filtering flask.6.11 Expendables:6.11.1 Double-Strength Broth,140-mL aliquots.6.11.2 Sterile Pipets,1 and 10-mL.6.11.3 Sterile 0.1%Peptone in 99-mL quantities.6.11.4 Sterile 0.1%Peptone as rinse water.6.11.5 Broth Cultures of Serratia marcescens,18 6 2 h.6.11.6 Sterile Membrane FiltersTest membranes.6.11.7 Petri Dishes,50-mm,containing 6 to 8-mL of agar.7.Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests
