ASTM E1413-2007 Standard Practice for Separation and Concentration of Ignitable Liquid Residues from Fire Debris Samples by Dynamic Headspace Concentration《用动态顶部空间浓缩法测定燃烧残骸试样中可燃性液态.pdf

《ASTM E1413-2007 Standard Practice for Separation and Concentration of Ignitable Liquid Residues from Fire Debris Samples by Dynamic Headspace Concentration《用动态顶部空间浓缩法测定燃烧残骸试样中可燃性液态.pdf》由会员分享，可在线阅读，更多相关《ASTM E1413-2007 Standard Practice for Separation and Concentration of Ignitable Liquid Residues from Fire Debris Samples by Dynamic Headspace Concentration《用动态顶部空间浓缩法测定燃烧残骸试样中可燃性液态.pdf（3页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E 1413 07Standard Practice forSeparation and Concentration of Ignitable Liquid Residuesfrom Fire Debris Samples by Dynamic HeadspaceConcentration1This standard is issued under the fixed designation E 1413; the number immediately following the designation indicates the year oforiginal ad

2、option or, in the case of revision, the 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 practice describes the procedure for separation ofsmall quantiti

3、es of ignitable liquid residues from fire debrissamples using the absorption/elution method of headspaceconcentration.1.2 Both positive and negative pressure systems are de-scribed.1.3 While this practice is suitable for successfully extractingignitable liquid residues over the entire range of conce

4、ntration,the headspace concentration methods are best used when a highlevel of sensitivity is required due to a very low concentrationof ignitable liquid residues in the sample.1.4 Alternate separation and concentration procedures arelisted in Section 2.1.5 This standard does not purport to address

5、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 Standards:2D 1193 Specificati

6、on for Reagent WaterE 752 Practice for Safety and Health Regulations Relatingto Occupational Exposure to Carbon Disulfide3E 1387 Test Method for Ignitable Liquid Residues in Ex-tracts from Fire Debris Samples by Gas ChromatographyE 1412 Practice for Separation of Ignitable Liquid Residuesfrom Fire D

7、ebris Samples by Passive Headspace Concen-tration With Activated Charcoal3. Summary of Practice3.1 The sample, preferably in its original container, isheated, forcing volatile compounds to vaporize. At the sametime, the headspace in the sample is drawn or pushed througha tube containing activated ch

8、arcoal which adsorbs the vapor-ized compounds.4. Significance and Use4.1 This practice is useful for preparing extracts from firedebris for later analysis by gas chromatography, GC/MS, orGC/IR.4.2 This is a very sensitive separation procedure, capable ofisolating quantities smaller than 0.1 L of ign

9、itable liquidresidue from a sample.4.2.1 Actual recovery will vary, depending on several fac-tors, including adsorption temperature, container size, andcompetition from the sample matrix.4.3 “This is a potentially destructive technique.” Portions ofthe sample subjected to this procedure may not be s

10、uitable forre-sampling. Therefore, a portion of the sample extract shouldbe saved for potential future analysis. Consider using passiveheadspace concentration as described in Practice E 1412.5. Apparatus5.1 Positive Pressure Apparatus:5.1.1 Sample Pressurization DeviceA system capable ofdelivering p

11、ressurized dry nitrogen (or other inert gas) at up to40 psi (276 kPa) to an orifice to be inserted into the bottom ofthe sample container.5.1.1.1 A needle valve capable of fine control of the flowrate of the dry nitrogen, at up to 1500 cc/min.5.1.1.2 A flow meter capable of measuring the flow of dry

12、nitrogen through the end of the charcoal adsorption tube at therate of 0 to 1500 cc/min.5.1.1.3 Container ClosureA device suitable for sealingthe container and directing the effluent nitrogen and vapors tothe charcoal tube.5.2 Negative Pressure Apparatus:5.2.1 Inlet and outlet systemA tube containin

13、g 1 cm ofcharcoal is fitted into the lid of the original container with a1This practice is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved April 15, 2007. Published June 2007. Original

14、lyapproved in 1991. Last previous edition approved in 2006 as E 1413 06.2For 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 AS

15、TM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.sleeve stopper. This serves as a filter for incoming room air. Avacuum is pulled on an adsorption tube also fitted into the lidof the original container with a sle

16、eve stopper.5.2.2 A vacuum system capable of pulling between 200 and1500 cc/min on the sample collection tube.5.2.3 A flow meter capable of measuring the flow of airthrough the end of the charcoal tube at the rate of 200 to 1500cc/min.5.3 Adsorption TubesSuitable absorption tubes may bemade by inser

17、ting a small (approximately 1 cm) plug of glasswool or cotton in the bottom of a Pasteur pipette (approxi-mately 5 mm diameter), then adding approximately 5 cm ofactivated charcoal, and finally, holding the charcoal in placewith an additional 1 cm of glass wool or cotton.5.3.1 Alternatively, charcoa

18、l tubes are available from com-mercial sources.5.3.2 The use of a different adsorbing media such as Tenaxis possible, but this results in complications in the desorbingphase because certain solvents cause the dissolution of theTenax. Tenax is best employed when desorption is to beperformed using a t

19、hermal operation.5.4 Heating SystemA heating mantel designed to fit theevidence container or an oven or a hot plate.5.4.1 An oven may be set up with any number of stations toallow for multiple sample preparation.5.5 Temperature Measuring DeviceA thermometer orthermocouple capable of measuring temper

20、atures in the rangeof 40 to 150C.6. Reagents and Materials6.1 Purity of ReagentsReagent grade or better chemicalsshall be used in all tests. Unless otherwise indicated, it isintended that all reagents conform to the specifications of theCommittee on Analytical Reagents of the American ChemicalSociet

21、y where such specifications are available.4Other gradesmay be used, provided it is first ascertained that the reagent isof sufficiently high purity to permit its use without lesseningthe accuracy of the determination.6.1.1 Purity of WaterUnless otherwise indicated, refer-ences to water shall be unde

22、rstood to mean reagent water asdefined by Type IV of Specification D 1193.6.2 Activated Charcoal (coconut).6.2.1 Test each new batch of charcoal for residual hydro-carbons by analyzing a concentrated extract of blank adsorp-tion media.6.3 Glass Wool, or cotton, free of extractable hydrocarbons.6.4 C

23、arbon Disulfide, GC grade.6.4.1 Read and follow the safety precautions described inPractice E 752.7. Sample Preparation7.1 Observe the appropriate procedures for handling anddocumentation of all submitted samples.7.1.1 Open and examine the fire debris sample in order todetermine that it is consisten

24、t with its description.7.1.1.1 Resolve any discrepancies between the submittingagents description of the evidence and the analysts observa-tion with the submitting agent prior to the completion of thereport.7.2 Place the sample in an appropriate, clean samplingcontainer, which is designed to be flus

25、hed by positive ornegative pressure.7.2.1 Ideally, the system will be designed so that themajority of samples can be extracted directly from the con-tainer in which they are delivered to the laboratory.8. Adsorption Procedure8.1 Positive Pressure:8.1.1 Place the sample container in the heating syste

26、m andconnect to the nitrogen source which will introduce nitrogeninto the bottom of the container, and to the exhaust lineconnected to the charcoal adsorbing tube.8.1.1.1 Direct connection of the charcoal tube to the samplecontainer is possible, unless an oven is used. Placement of thecharcoal tube

27、outside the oven requires the use of an interven-ing line which must be carefully cleaned between uses toremove any adsorbed or condensed residues.8.1.2 PressurizationDeliver nitrogen to the samplethrough a18 in. (3.2 mm) line on the inlet side of the containerat a pressure of 40 psig (276 kPa) upst

28、ream of the needle valvecontrolling the flow rate. Connect a14 in. (6.35 mm) line on thedownstream side of the container to the charcoal tube. Attachthe flow meter to the outlet side of the charcoal tube, and usethe needle valve to adjust the flow to the rate determined to beoptimum for this system.

29、8.1.2.1 Determine the optimum flow rate by placing knownquantities of gasoline, kerosene, mineral spirits, and diesel fuelonto standard substrate material such as squares of carpeting orfilter paper. Determine the percent recovery by gas chromato-graphic analysis. The flow rate resulting in the high

30、est percentrecovery is the optimum.8.1.2.2 Remove the flow meter once the flow is adjusted.Check the flow at least once after the sample has reached thefinal temperature.8.1.3 Turn on the heating system and increase the tempera-ture to no more than 150C. At this temperature, mostpetroleum distillate

31、s can be volatilized in less than one hour,and there will be a minimum of pyrolysis of common poly-mers.8.1.3.1 Allow 20 min for the sample to reach temperature,and an additional one hour flushing the sample out. At thispoint, turn off the gas. The charcoal adsorption tube is nowready for elution.8.

32、1.3.2 The adsorption time may be reduced if it can beshown that equal or superior recovery rates are achieved in thereduced time period.8.2 Negative Pressure:8.2.1 Place the inlet and outlet adsorption tubes in the lid ofthe evidence container.8.2.2 Place the temperature measuring device in the lid

33、ofthe container.4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United

34、States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.E14130728.2.3 Apply a vacuum to the sample adsorption tube. Theflow through the tube should be between 200 and 1500 cc/min.8.2.4 Heat the evidence container to 90C and hold at thattemperature for 5 m

35、in. After 5 min at 90C, turn off thevacuum, and the sample adsorption tube is ready to be eluted.9. Elution Procedure9.1 Code or label an approximately sized vial or test tubewith the case number, sample number, date, separation method,and analysts initials.9.2 Remove the charcoal tube from the samp

36、le outlet lineand insert into the properly labeled test tube. Allow to cool toroom temperature. Trickle one mL of elution solvent throughthe charcoal tube and into the test tube. An aspirator bulb maybe necessary in order to push the solvent through the charcoal.9.2.1 Alternatively, the charcoal may

37、 be removed from thetube and agitated in a container with elution solvent.9.2.2 Any method of elution may be used if it can be shownthat adsorbed residues are effectively eluted.10. Sealing10.1 A septum seal vial may be used for collecting andsealing the elution solvent extract.10.2 A test tube cont

38、aining CS2may be sealed by theaddition of water which will float on top of the CS2and reduceits evaporation.10.3 Preserve the extract so that it may be re-analyzed.Guidance on extract preservation may be found in Test MethodE 1387.11. Blanks and Standards11.1 Frequent blanks must be run on every app

39、aratus usedfor this procedure.11.1.1 Prepare a blank by connecting an empty container tothe adsorption apparatus, and running the adsorption proceduredescribed in Section 8 for the normal length of time. Elute thecharcoal tube according to Section 9, and analyze the extractaccording to Test Method E

40、 1387.11.1.1.1 If an internal standard is routinely used, include aninternal standard in the blank.11.2 Charcoal may be activated and cleaned by heating in a400C oven for 4 h and cooling in a desiccator.11.3 Check the adsorption efficiency periodically by run-ning this procedure on a sample containi

41、ng a known volume ofstandard ignitable liquid.12. Keywords12.1 dynamic headspace concentration; fire debris samplesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly ad

42、vised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely 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, eithe

43、r reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend.

44、If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on 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).E1413073