1、Designation: G 120 01Standard Practice forDetermination of Soluble Residual Contamination bySoxhlet Extraction1This standard is issued under the fixed designation G 120; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of l
2、ast 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 practice describes a procedure for the determina-tion of residual contamination in systems and componentsrequirin
3、g a high level of cleanliness, such as oxygen, bySoxhlet extraction.1.2 This practice may be used for extracting nonvolatile andsemivolatile residues from solids such as new and used gloves,new and used wipes, contaminated test specimens or controlcoupons, small pieces of hardware, component softgoo
4、ds, etc.When used with proposed cleaning materials (wipes, gloves,etc.), from the cleaning materials this practice may be used todetermine the potential of the proposed solvent to extractcontaminants (plasticizers, residual detergents, brighteners,etc.) and deposit them on the surface being cleaned.
5、1.3 This practice is not suitable for the evaluation ofparticulate contamination.1.4 The values stated in SI units are standard.1.5 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
6、appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2E 1235 Test Method for Gravimetric Determination of Non-volatile Residue (NVR) in Environmentally Controll
7、edAreas for Spacecraft3F 331 Test Method for Nonvolatile Residue of SolventExtract from Aerospace Components (Using Rotary FlashEvaporator)3G93 Practice for Cleaning Methods for Material andEquipment Used in Oxygen-Enriched Environments43. Terminology3.1 Definitions:3.1.1 contaminant, nunwanted mole
8、cular and particulatematter that could affect the performance of the components ormaterials upon which they reside.3.1.2 contamination, na process of contaminating.3.1.3 nonvolatile residue (NVR), nresidual molecular andparticulate matter remaining following the filtration of asolvent containing con
9、taminants and complete evaporation ofthe solvent at a specified temperature.3.1.4 particle (particulate contaminant), n a piece ofmatter in a solid state with observable length, width, andthickness.3.1.4.1 DiscussionThe size of a particle is usually definedby its greatest dimension and is specified
10、in micrometres.3.1.5 molecular contaminant , nnon-particulate contami-nation.3.1.5.1 DiscussionA molecular contaminant may be in agaseous, liquid, or solid state and may be uniformly ornonuniformly distributed.3.1.5.2 DiscussionMolecular contaminants account formost of the NVR.3.1.6 control coupon (
11、witness coupon), n a coupon madefrom the same material and prepared in exactly the same wayas the test coupons, which is used to verify the validity of themethod or part thereof.3.1.6.1 DiscussionIn this test method, the control couponwill be contaminated in the same manner as the test couponsand wi
12、ll be subjected to the identical extraction procedure.4. Summary of Practice4.1 The sample is placed in an extraction thimble orbetween two plugs of glass wool and contaminants are ex-tracted using an appropriate solvent in a Soxhlet extractor. Thesolvent is brought to the boiling point; the pure so
13、lvent vaporstravel to the condenser where they condense and drip into thethimble. When the liquid level in the thimble reaches the top of1This practice is under the jurisdiction of ASTM Committee G04 on Compat-ibility and Sensitivity of Materials in Oxygen Enriched Atmospheres and is thedirect respo
14、nsibility of Subcommittee G04.02 on Recommended Practices.Current edition approved Sept. 10, 2001. Published January 2002. Originallypublished as G120 93. Last previous edition G 120 95.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 15.03.4Annual Book of ASTM Standards
15、, Vol 14.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the Soxhlet siphon, the solvent and extracted soluble contami-nant are siphoned back into the boiler. This process is allowedto continue for several hours. The solvent and e
16、xtract are thenconcentrated or dried for analysis.5. Significance and Use5.1 It is expected that this test method will be suitable toidentify and quantify contaminants found in systems, systemmaterials, and components used in systems requiring a highlevel of cleanliness, such as oxygen. Softgoods su
17、ch as sealsand valve seats can be tested as received. Gloves and wipes, orsamples thereof, to be used in the cleaning operation can beevaluated prior to use to ensure that the proposed cleaningsolvent does not extract contaminants and residues on thesurface to be cleaned.5.2 Wipes or other cleaning
18、equipment can be tested afteruse to determine the amount of contaminant removed from asurface. This procedure can be used to obtain samples for NVRanalysis using contaminated control coupons that were sub-jected to the cleaning process as controls to validate cleaningoperations.5.3 The selection of
19、the solvent requires some knowledge ofthe contaminant (see Practice G93for recommendations). If anonvolatile residue (NVR) analysis is to be performed on themolecular contaminant, the boiling point of the solvent shall besignificantly lower than that of the contaminant. For otheranalytical methods,
20、the tester must know the accuracy of theanalytical methods, and the solvent shall be chosen so as not tointerfere with the selected analytical method. To identify thecomposition of the NVR, analytical methods such as infraredspectroscopy or gas chromatography/mass spectroscopy havebeen used satisfac
21、torily.6. Apparatus6.1 Soxhlet extractor500 mL evaporation flask and asso-ciated equipment as shown in Fig. 1.6.2 Boiling chipssolvent extracted.6.3 Water bathheated with temperature control of 65C.6.4 Thimblesglass or paper.6.5 Heating mantlerheostat controlled.6.6 Balancerange to a minimum of 50 g
22、 with an accuracyof 0.1 mg.6.7 Evaporatorrotary.6.8 500 mL concentrator flask7. Reagents7.1 Solvents that can be used to prepare standard contami-nant solutions include the following: 2-propanol, 2-butanone,hexane, methylene chloride, and perfluorinated carbon fluids.7.2 Purity of ReagentsReagent gr
23、ade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.5Other grades may be used,provided it is first ascertained
24、 that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.NOTE 1Warning: Solvents such as 2-propanol and 2-butanone arehighly flammable. The reader should refer to appropriate safe handlingprocedures.7.3 Watershall meet the requirements of D
25、 1193, Type II.8. Procedure8.1 Prepare the sample for placement in the extractor.8.1.1 To determine the amount of extractable material in awiping cloth (new or used), cut out a test section approximately30 centimetres (cm) square, accurately measure and calculatethe area (A) in square centimetres, a
26、nd weigh the section ingrams to the nearest tenth of a milligram (W1). Record the areaand weight.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analytic
27、al Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.FIG. 1 Soxhlet Extraction ApparatusG1200128.1.1.1 If the NVR is to be determined on a used wipingcloth in an effort
28、 to assess the cleanliness of a part or system,a NVR analysis shall be performed on an unused representativesample of the cloth, with the same surface area, prior to useaccording to E 1235or F 331. Record this NVR as W3in mg/gor as W4in mg/cm2. This NVR value must be subtracted fromthat determined f
29、or the contaminated cloth.8.1.2 To determine the amount of extractable material in aglove to be used in a cleaning operation, cut several rectangularstrips from the fingers and palm, the areas that would typicallybe exposed to the cleaning solvent, weigh in grams to thenearest tenth of a milligram a
30、nd record the weight (W1).Determine the dimensions of each strip in cm and record thetotal surface area of the strips (A) in square centimetres.8.1.3 To determine the amount of NVR on control coupons,measure the total contaminated surface area (i.e., front, orfront, back, and sides) in square centim
31、etres and weigh ingrams to the nearest tenth of a milligram. Record the surfacearea (A) and weight (W1).8.1.4 To determine the amount of NVR on small parts,measure and record the total surface area (A) in squarecentimetres and weight in grams to nearest tenth of a milligram(W1) to be evaluated.8.2 P
32、lace the material to be extracted in an extractionthimble or between two glass wool plugs in the extractor.8.2.1 The glass wool used for the plugs shall be washedprior to use with the solvent to be used for the extraction.8.3 Place 300 mL of the extraction solvent into the 500 mLflat bottom boiling
33、flask containing one or two clean boilingchips. Place the flask in a heating mantle (or water bath that canbe heated 15 to 20C above the boiling point of the solvent)and attach the extractor to the flask.Attach the condenser to theextractor, turn on the cooling water to the condenser, bring theflask
34、 to a boil and extract the sample for six hours.8.3.1 Extract especially thick or dense materials overnight.If any doubt exists, it is recommended that extractions beperformed for different times (on new samples each time) toverify that the shorter extraction time removed all the extract-ables.8.4 A
35、llow the extract to cool after the extraction is com-plete.8.5 Assemble the rotary evaporator.8.6 Carefully pour the extract from the 500 mL boiling flaskinto the 500 mLconcentrator flask. Rinse the 500 mLflask with25 to 50 mL portions of fresh reagent grade extraction solventand add the rinse solut
36、ion to the concentrator flask. Repeat therinse process two more times to complete the quantitativetransfer.8.7 Attach the concentrator flask to the rotary evaporator.Partially immerse the flask in a water bath approximately 15 to20C above the boiling point of the solvent. When the apparentvolume of
37、liquid reaches approximately 5 mL, remove the flaskfrom the water bath and allow the flask to cool for at least tenminutes at room temperature.8.8 Determine the weight (W2) of the nonvolatile residue ingrams to the nearest tenth of a milligram using E 1235 orF 331.9. Calculation9.1 Calculate the non
38、volatile residue as follows:9.1.1 For new materials, wipes, gloves, etc., the total NVRper unit weight is:NVR 51000*W2W1(1)where:NVR = nonvolatile residue, mg/g sample,W1= weight of the sample prior to extraction, g, andW2= weight of the nonvolatile residue, g.9.1.2 For new materials, wipes, gloves,
39、 etc., NVR by unitarea is:NVR 51000*W2A(2)where:NVR = nonvolatile residue, mg/cm2of sample,A = surface area of the sample, cm2, andW2= weight of the nonvolatile residue, g.9.1.3 For used material, the total NVR per unit weight in is:NVR 51000*W2W12 W3(3)where:NVR = nonvolatile residue, mg/cm2of samp
40、le,W1= weight of the sample prior to extraction, g,W2= weight of the nonvolatile residue, g, andW3= NVR of new sample, mg/g.9.1.4 For used material, the total NVR per unit area is:NVR 51000*W2A2 W4(4)where:NVR = nonvolatile residue, mg/cm2of sample,W2= weight of the nonvolatile residue, g,A = surfac
41、e area of the sample, cm2, andW4= NVR of new sample, mg/cm2.10. Report10.1 The report shall include the following:10.1.1 Identification of the material being extracted (includ-ing tradename, proper chemical name, ASTM designation, lotnumber, batch number, and manufacturer),10.1.2 Extraction solvent,
42、10.1.3 Extraction time,10.1.4 Evaporation temperature,10.1.5 Method used to determine the weight of the NVR,10.1.6 Value of the NVR (using formula 1, 2, 3 or 4).11. Precision and Bias11.1 PrecisionThe precision of the procedure in PracticeG 120 is being determined.11.2 BiasSince there is no accepted
43、 reference material fordetermining the bias for the procedure in Practice G 120 biashas not been determined.12. Keywords12.1 contaminant; contamination; extraction; nonvolatileresidue; oxygen systems; Soxhlet extractionG120013ASTM International takes no position respecting the validity of any patent
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