ASTM_D_4198_-_20.pdf

Designation:D419820Standard Test Methods forEvaluating Absorbent Pads Used with Membrane Filters forBacteriological Analysis and Growth1This standard is issued under the fixed designation D4198;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 These test methods cover the determination of thenutrient-holding capacity and the toxic or nutritive effect onbacterial growth of organisms retained on a membrane filter,when the absorbent pad being tested is used as a nutrientreservoir and medium supply source for the retained bacteria.1.2 The tests described are conducted on 47 mm diameterdisks,although other size disks may be employed for bacterialculture techniques.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Specification for Reagent WaterD3508 Method for Evaluating Water Testing MembraneFilters for Fecal Coliform Recovery(Withdrawn 1995)33.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this standard,refer toTerminology D1129.4.Summary of Test Methods4.1 Test Method A involves saturating a 47 mm absorbentpad with water and determining the volume of water held bythe pad by weighing the pad dry and when fully saturated.4.2 Test Method B involves culturing micro-organisms fromsuspensions of pure cultures on a 0.45 m membrane filter,which is placed on the test absorbent pad saturated with theappropriate growth medium.The resultant cultures are com-pared to cultures grown on spread plates and to membranefilters placed directly on agar with no absorbent pad.5.Significance and Use5.1 These test methods are appropriate for qualifying absor-bent pads used with membrane filters for bacteriologicalenumeration.5.1.1 The test methods described are applicable to qualitycontrol testing of absorbent pads by the suppliers and users ofthese pads and to specification testing of absorbent padsintended for use with membrane filters in bacteriologicalenumeration.5.2 Other pure culture organisms and their appropriateculture medium may be substituted for the E.coli and M-FCmedia for specification testing,as required.6.Apparatus6.1 Filtration Units for membrane filters with side-arm flaskand tubing.6.2 Vacuum Source.6.3 Vortex Mixer or similar mixer.1These test methods are under the jurisdiction of ASTM Committee D19 onWater and are the direct responsibilities of Subcommittee D19.08 on Membranesand Ion Exchange Materials.Current edition approved Nov.1,2020.Published November 2020.Originallyapproved in 1982.Last previous edition approved in 2011 as D4198 82(2011)which was withdrawn July 2020 and reinstated in November 2020.DOI:10.1520/D4198-20.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.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.16.4 Forceps,flat-bladed.6.5 Incubator capable of maintaining temperatures of 44.56 0.2 C.6.6 Stereoscopic Microscope and Illuminator.6.7 Illuminated Magnifying Stand for counting colonies onagar spread plates.6.8 Hand Tally Counter.6.9 Autoclave.6.10 Analytical Balance readable to the nearest 1 mg.6.11 Petri Dish,50 mm,nonsterile.6.12 Expendable Equipment:6.12.1 Filters(gridded,0.45 m,47 mm)sterile,for watertesting.6.12.2 Absorbent pads(47 mm),sterile for the growth test.6.12.3 Petri dishes,sterile 50 mm and 100 mm.6.12.4 Pipets,sterile,10 mL,0.1 mL graduations,accuracyof 65%.6.12.5 Test tubes,sterile,20 mL,with screw caps.6.12.6 Bent glass r