1、Designation: G120 01 (Reapproved 2008)G120 15Standard Practice forDetermination of Soluble Residual Contamination bySoxhlet Extraction1This standard is issued under the fixed designation G120; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、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 practice describes a procedure for the determination of residual contamination in systems a
3、nd components materialsto be used within or in contact with hardware requiring a high level of cleanliness, such as oxygen, components for oxygen service,by Soxhlet extraction.1.2 This practice may be used for extracting nonvolatile and semivolatile residues from solids such as new and used gloves,
4、newand used wipes,wipers, contaminated test specimens or control coupons, small pieces of hardware, component softgoods,pieceparts (metallic or nonmetallic), etc. When used with proposed consumable cleaning materials (wipes,(wipers, gloves, etc.), fromthe cleaning materials this practice may be used
5、 to determine the potential of the proposed solvent to extract contaminants(plasticizers, residual detergents, brighteners, etc.) from the cleaning material and deposit them on the surface being cleaned.1.3 This practice is not suitable for the evaluation of particulate contamination.1.4 The values
6、stated in SI units are standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitation
7、s prior to use.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterE1235 Test Method for Gravimetric Determination of Nonvolatile Residue (NVR) in Environmentally Controlled Areas forSpacecraftE1560 Test Method for Gravimetric Determination of Nonvolatile Residue From Cle
8、anroom WipersE1731 Test Method for Gravimetric Determination of Nonvolatile Residue from Cleanroom GlovesF331 Test Method for Nonvolatile Residue of Solvent Extract from Aerospace Components (Using Flash Evaporator)G93 Practice for Cleaning Methods and Cleanliness Levels for Material and Equipment U
9、sed in Oxygen-Enriched EnvironmentsG127 Guide for the Selection of Cleaning Agents for Oxygen-Enriched SystemsG136 Practice for Determination of Soluble Residual Contaminants in Materials by Ultrasonic ExtractionG144 Test Method for Determination of Residual Contamination of Materials and Components
10、 by Total CarbonAnalysis Usinga High Temperature Combustion Analyzer3. Terminology3.1 Definitions:3.1.1 contaminant, nunwanted molecular and particulate matter that could affect the performance of the components ormaterials upon which they reside.3.1.2 contamination, na process of contaminating.1 Th
11、is practice is under the jurisdiction of ASTM Committee G04 on Compatibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is the directresponsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved Sept. 1, 2008Oct. 1, 2015. Published October 20082015. Ori
12、ginally approved in 1993. Last previous edition approved in 20012008 asG120 01.G120 01(2008). DOI: 10.1520/G0120-01R08.10.1520/G0120-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume inf
13、ormation, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately
14、depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA
15、 19428-2959. United States13.1.3 control coupon (witness coupon), na coupon made from the same material and prepared in exactly the same way as thetest coupons, and which is used to verify the validity of the method or part thereof.3.1.3.1 DiscussionIn this test method, the control coupon will be co
16、ntaminated in the same manner as the test coupons and will be subjected to theidentical extraction procedure.3.1.4 molecular contaminant, nnon-particulate contamination.3.1.4.1 DiscussionA molecular contaminant may be in a gaseous, liquid, or solid state and may be uniformly or non-uniformly distrib
17、uted.3.1.4.2 DiscussionMolecular contaminants account for most of the NVR.3.1.5 nonvolatile residue (NVR), nresidual molecular and particulate matter remaining following the filtration of a solventcontaining contaminants and complete evaporation of the solvent at a specified temperature.3.1.6 partic
18、le (particulate contaminant), na piece of matter in a solid state with observable length, width, and thickness.3.1.6.1 DiscussionThe size of a particle is usually defined by its greatest dimension and is specified in micrometres.3.1.5 molecular contaminant , nnon-particulate contamination.3.1.5.1 Di
19、scussionA molecular contaminant may be in a gaseous, liquid, or solid state and may be uniformly or nonuniformly distributed.3.1.5.2 DiscussionMolecular contaminants account for most of the NVR.3.1.6 control coupon (witness coupon), na coupon made from the same material and prepared in exactly the s
20、ame way as thetest coupons, which is used to verify the validity of the method or part thereof.3.1.6.1 DiscussionIn this test method, the control coupon will be contaminated in the same manner as the test coupons and will be subjected to theidentical extraction procedure.4. Summary of Practice4.1 Th
21、e samplespecimen is placed in an extraction thimble or between two plugs of glass wool and contaminants are extractedusing an appropriate solvent in a Soxhlet extractor. The solvent is brought to the boiling point; point and the pure solvent vaporstravel to the condenser where they condense and drip
22、 into the thimble. When the liquid level in the thimble reaches the top of theSoxhlet siphon, the solvent and extracted soluble contaminant are siphoned back into the boiler. This process is allowed to continuefor several hours. The solvent and extract are then concentrated or dried for analysis.5.
23、Significance and Use5.1 It is expected that this practicewill practice will be suitable to identify and quantify contaminants found in systems, systemmaterials, and components used in systems requiring a high level of cleanliness, such as oxygen. Softgoods components for oxygenservice. Nonmetallic p
24、iece parts such as seals and valve seats can be tested as received. GlovesWarningIf parts being tested areto be subsequently installed in an oxygen-enriched system, residual extraction solvent remaining in the part due to inadequatedrying may increase the susceptibility of the system to ignition. Th
25、e extraction solvent shall be thoroughly removed from the partsprior to service. and wipes, or samples thereof, to be used in the cleaning operation can be evaluated prior to use to ensure thatthe proposed cleaning solvent does not extract contaminants and residues on the surface to be cleaned.G120
26、1525.2 Processing materials such as gloves and wipers, or samples thereof, to be used in the cleaning operation can be evaluatedprior to use to ensure that the proposed cleaning solvent does not extract contaminants that may be deposited as residues on thesurface to be cleaned.NOTE 1Test methods tha
27、t do not require Soxhlet equipment, such as Test Methods E1560 and E1731, may be suitable alternatives for evaluation ofprocessing materials. Test Method G144 with Practice G136 may be suitable for use when the material to be tested is not degraded by sonication.However, results from this test metho
28、d cannot be directly compared to results from other test methods. Soxhlet extraction may be more aggressive thanother extraction methods.5.3 WipesWipers or other cleaning equipmentsupplies can be tested before and after use to determine the amount of contaminantremoved from a surface. The type of co
29、ntaminant removed from the surface may also be determined by qualitative analysis of theextracted NVR using analytical methods such as Fourier Transform Infrared (FTIR). This procedure can be used to obtain samplesfor NVR analysis using contaminated control coupons that were subjected to the cleanin
30、g process as controls to validate cleaningoperations.5.4 The selection of the solvent requires some knowledge of the contaminant (see Practice G93 for recommendations). If anonvolatile residue (NVR) analysis is to be performed on the molecular contaminant, the boiling point of the solvent shall besi
31、gnificantly lower than that of the contaminant. For other analytical methods, the tester must know the accuracy of the analyticalmethods, and the solvent shall be chosen so as not to interfere with the selected analytical method. To identify the compositionof the NVR, analytical methods such as infr
32、ared spectroscopy or gas chromatography/mass spectroscopy have been usedsatisfactorily.6. Apparatus6.1 Soxhlet extractor500 mL evaporation flask and associated equipment as shown in Fig. 1.6.2 Boiling chipssolvent extracted.6.3 Water bathheated with temperature control of 65 C.6.4 Thimblesglass or p
33、aper.FIG. 1 Soxhlet Extraction ApparatusG120 1536.5 Heating mantlerheostat controlled.6.6 Balancerange to a minimum of 50 g with an accuracy of 0.1 mg.6.7 Evaporatorrotary.6.8 500 mL concentrator flask.NOTE 2Larger extraction systems may be used for batch extraction of wipers to be used to sample NV
34、R on surfaces or to extract NVR from largercomponents. The item to be extracted must be small enough to be fully immersed in solvent within the extraction chamber.7. Reagents7.1 Examples of solvents commonly used for Soxhlet extraction are ethanol, 2-propanol, 2-butanone, hexane, dichloromethane,pro
35、panone, ethyl acetate, and the azeotrope of ethyl acetate/cyclohexane. Different solvents will vary in removal efficiency fordifferent types of contaminants and should be selected based on the contaminants of greatest concern. The solvent used shall berecorded in the test report.SolventsWarningSolve
36、nts such as ethanol, 2-propanol, 2-butanone, hexane, and ethyl acetate are highly flammable. Thereader should refer to appropriate safe handling procedures. that can be used to prepare standard contaminant solutions include thefollowing: 2-propanol, 2-butanone, hexane, methylene chloride, and perflu
37、orinated carbon fluids.NOTE 3Hydrofluorocarbons and hydrofluoroethers may be acceptable choices but are less effective at removing hydrocarbon-based NVR than ethylacetate or hexane.NOTE 4Ethanol and 2-propanol are the least effective at removing NVR but may be used when they reflect actual solvent u
38、sage in service.7.1.1 When testing processing materials such as gloves and wipers, a solvent that is representative of the service conditions ofthe material should be selected.7.1.2 Many polymeric materials are incompatible with solvents. Refer to Guide G127 for guidance on material compatibility.Ex
39、traction may also leach desirable additives, altering the performance of the polymer. Gloves and wipers that are attacked by anextraction solvent should not be used with that solvent in production.7.1.3 Nonmetallic piece parts should be tested using solvents that are known to be compatible with the
40、material. Cracking,discoloration, or significant weight loss are evidence of solvent attack. Continued release of NVR in successive extraction cyclesmay also indicate that the material is incompatible with the extraction solvent.7.1.3.1 For extraction of unfilled nonmetallic material, there must be
41、sufficient insolubility between the material and extractionsolvent such that there is no dissolution of the material.7.1.3.2 For extraction of filled nonmetallic material, the filler must not be soluble in the extraction solvent at the extractiontemperature and sufficient insolubility or crosslinkin
42、g must be present to prevent migration of filler during the extraction, such thatthe extractant remains clear and free of filler.7.1.3.3 To evaluate surface contamination on a nonmetallic piece part that is not compatible with extended exposure to thesolvent but is compatible with brief exposure, th
43、e surface of the part may be sampled by the wipe method described in section 5.3followed immediately by drying.7.2 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analy
44、tical Reagents of the American Chemical Society where suchspecifications are available.3 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.Alternatively, the solvent may be p
45、urified by distillation priorto use.NOTE 1Warning: Solvents such as 2-propanol and 2-butanone are highly flammable.The reader should refer to appropriate safe handling procedures.7.3 WaterWater for extractionshall meet the requirements of D1193, Type II.8. Procedure8.1 Prepare the samplespecimen for
46、 placement in the extractor.8.1.1 To determine the amount of extractable material in a wiping cloth (new or used), cut out a test section approximately 30centimetrescm2 (cm) square, , accurately measure and calculate the area (A) in squarecm2 centimetres, , and weigh the section ingrams to the neare
47、st tenth of a milligram (W1). Record the area and weight.8.1.1.1 If the NVR is to be determined on a used wiping cloth in an effort to assess the cleanliness of a part or system, a NVRanalysis shall be performed on an unused representative sample of the cloth, with the same surface area, prior to us
48、e accordingto Test Method E1235 or Test Method F331. Low-linting cotton cleanroom wipers have been found to be acceptable for NVR wipesampling. Monofilament polyester wipers, while less absorbent, release fewer fibers than cotton wipers and may be preferred in3 Reagent Chemicals, American Chemical S
49、ociety Specifications , , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Analytical Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville, MD.G120 154critical applications. For greater accuracy, the wiping cloths should be pre-extracted as a batch prior to use. Record this NVR asW3 in mg/g or as W4 in mg/cm2. This NVR value must be s
