1、Designation: D 3861 91 (Reapproved 2003)Standard Test Method forQuantity of Water-Extractable Matter in Membrane Filters1This standard is issued under the fixed designation D 3861; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 covers the gravimetric determinationof the water-extractable material present in membrane
3、filtersand is applicable over the complete concentration range ofextractables.1.2 The analyst should be aware that adequate collaborativedata for precision and bias statements as required by PracticeD 2777 is not provided. See Section 11 for details.1.3 This standard does not purport to address all
4、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 Standards:2D 1129 Terminology Rel
5、ating to WaterD 1193 Specification for Reagent WaterD 2777 Practice for Determination of Precision and Bias ofApplicable Methods of Committee D19 on Water3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D 1129.4. Summary of Test Method4.1 The quanti
6、ty of water-soluble extractables present inmembrane filters is determined by immersing the preweighedmembrane in boiling reagent grade water for an extended time,then drying and reweighing the membrane. A control mem-brane is employed to eliminate weighing errors caused bybalance changes or changing
7、 moisture content of the mem-brane in the weighing procedures. Weight changes of thecontrol membrane are applied as a correction factor to theweight change of the test membrane filters.5. Significance and Use5.1 The presence of water-soluble extractables in membranefilters can create errors in test
8、procedures employing membranefilters. However, these errors can be eliminated or significantlyreduced if the quantity of water-soluble extractables of thespecific membrane is previously determined. Certain mem-brane filter uses require specifications of maximum water-soluble extractable levels. This
9、 test method is intended to be arapid test to determine the loss of water-soluble compoundssuch as plasticizers or wetting agents from filtration mem-branes. This test method is not designed to predetermine theperformance of a filter, but is significant in determining thepercent extractables of memb
10、ranes from different sources andlot variations from a single source.6. Apparatus6.1 Beaker, borosilicate glass, 300-mL capacity.6.2 Forceps, stainless steel, unserrated tips.6.3 Desiccator.6.4 Drying Oven, with thermostatic control.6.5 Analytical Balance, sensitivity 0.01 mg.6.6 a-Emitting Polonium
11、Source3(to discharge staticcharge in balance).6.7 Humidity-Controlled Room or Hood, for balance.6.8 Evaporating Dishes, glass, having sides or other meansto keep test filters on the dish while drying.7. Reagents and Materials7.1 Purity of Water Unless otherwise indicated, refer-ences to water shall
12、be understood to mean Type III reagentwater conforming to Specification D 1193.7.2 Membrane Filters, 47-mm diameter (same type as thoseunder test).8. Preparation of Apparatus and Materials8.1 Preparation of Samples and Apparatus:8.1.1 Select 47-mm diameter sample (Note 1) membranefilters for the tes
13、t, and label with water-resistant ink.NOTE 1Square or rectangular membrane of equivalent area (17.4 cm2) may be used.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 editio
14、n approved June 15, 1991. Published December 1991. Originallyapproved in 1979. Last previous edition approved in 1991 as D 3861 91.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
15、tion, refer to the standards Document Summary page onthe ASTM website.3The “Staticmaster,” available from Nuclear Products Inc., El Monte, CA, hasbeen found suitable for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.8.
16、1.2 To provide a “control filter,” select and label oneadditional 47-mm membrane filter of the same type as thosebeing tested. Take the control filter through all the drying andweighing steps, but do not extract.8.1.3 Set drying oven at 70C.9. Procedure9.1 Heat the test and control filters in the ov
17、en at 70C for15 min.9.1.1 Remove filters from the oven and place them in thedesiccator for at least 30 min at room temperature.9.1.2 Remove filters from desiccator and place them inbalance room atmosphere for 10 to 15 min.9.1.3 In a humidity-controlled balance room or hood, weightest filters and con
18、trol filter to 0.1 mg. Employ a staticeliminator in the balance.9.1.3.1 Place the “control” filter in the desiccator.9.2 Heat 200 mLof the reagent grade water to boiling, inserttest membrane filters, and continue heating with mild boilingfor 30 min. No more than four membrane filters should beextrac
19、ted in a single beaker of water. If water level is reducedbeyond 50 % of original level, add water to bring volume tooriginal level.9.3 Remove the filters using unserrated flat-bladed forceps,place them on clean glass evaporating dishes, and dry them inthe oven at 70C for 60 6 10 min.9.3.1 Remove th
20、e test filters from the oven and examinethem to determine that none of the filter material has broken offin the handling and extraction. If any filter has been damaged,discard it and select a replacement for test.9.4 Place the test filters in the desiccator with the controlfilter for 30-min minimum
21、time.9.5 Place the filters in balance room or hood atmosphere for10 to 15 min. Then weigh test and control filters to 0.1 mg todetermine final weight.10. Calculation10.1 Determine weight change of the test filter by subtract-ing the final weight W2from the initial weight W1of the testfilter.10.2 Det
22、ermine weight change of the control filter bysubtracting the initial weight W3from the final weight W4ofthe control filter.10.2.1 If the weight change of the control filter exceeds 2mg, the test should be rerun.10.3 Determine corrected weight change of the test filter byadding weight change of the c
23、ontrol filter (W4 W3)totheweight change of the test filter.10.4 Determine percent extractables as follows:E 5W12 W2! 1 W42 W3!W13 100where:E = percent extractables,W1= initial weight of test filter,W2= final weight of test filter,W3= initial weight of control filter, andW4= final weight of control f
24、ilter.11. Precision and BiasNOTE 2The range of percent extractables for the samples tested forthe round-robin test to determine precision was 1.06 to 3.09 % extract-ables.11.1 The precision and bias of this test method was basedupon five laboratories with five operators using membranefilters of thre
25、e different micron ratings.11.1.1 Precision:11.1.1.1 The overall precision of this test method may beexpressed as follows:St5 0.54X 2 0.37where:St= overall precision, %, andX = concentration of water extractables.11.1.1.2 The single-operator precision may be expressed asfollows:So5 0.64X 2 0.61where
26、:So= single-operator precision, %, andX = concentration of water extractables.11.1.2 BiasMicroporous membranes are inherently vari-able and therefore no true or absolute value can be established.A bias statement is not applicable to this procedure.12. Keywords12.1 extractable; filter; membraneASTM I
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28、ely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand
29、should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on
30、Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 3861 91 (2003)2
