1、Designation: E1412 16Standard Practice forSeparation of Ignitable Liquid Residues from Fire DebrisSamples by Passive Headspace Concentration WithActivated Charcoal1This standard is issued under the fixed designation E1412; the number immediately following the designation indicates the year oforigina
2、l 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 This practice describes the procedure for separation ofsmall quant
3、ities of ignitable liquid residues from samples offire debris using an adsorbent material to extract the residuefrom the static headspace above the sample, then eluting theadsorbent with a solvent.1.2 While this practice is suitable for successfully extractingignitable liquid residues over the entir
4、e range of concentration,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.1.2.1 Unlike other methods of separation and concentration,this practice is essentially nondestructive.1.3
5、Alternate separation and concentration procedures arelisted in the referenced documents (see Practices E1386,E1388, E1413, and E2154).1.4 This practice does not replace knowledge, skill, ability,experience, education, or training and should be used inconjunction with professional judgment.1.5 The va
6、lues stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 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 s
7、afety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1386 Practice for Separation of Ignitable Liquid Residuesfrom Fire Debris Samples by Solvent ExtractionE1388 Practice for Sampling of Headspace Vapors from F
8、ireDebris SamplesE1413 Practice for Separation of Ignitable Liquid Residuesfrom Fire Debris Samples by Dynamic Headspace Con-centrationE1459 Guide for Physical Evidence Labeling and RelatedDocumentationE1492 Practice for Receiving, Documenting, Storing, andRetrieving Evidence in a Forensic Science L
9、aboratoryE1618 Test Method for Ignitable Liquid Residues in Extractsfrom Fire Debris Samples by Gas Chromatography-MassSpectrometryE2154 Practice for Separation and Concentration of Ignit-able Liquid Residues from Fire Debris Samples by Pas-sive Headspace Concentration with Solid Phase Microex-tract
10、ion (SPME)E2451 Practice for Preserving Ignitable Liquids and Ignit-able Liquid Residue Extracts from Fire Debris Samples3. Summary of Practice3.1 Charcoal in some form of an adsorption package isplaced in the sample container to adsorb ignitable liquidresidues. The container may be heated or left a
11、t ambienttemperature. The charcoal is removed and eluted with asuitable elution solvent as listed in 6.3.4. Significance and Use4.1 This practice is useful for preparing extracts from firedebris for later analysis by gas chromatography mass spec-trometry.4.2 This is a very sensitive separation proce
12、dure, capable ofisolating quantities smaller than110 L of ignitable liquidresidue from a sample.5. Apparatus5.1 Heating SystemAn oven, or a heating mantle to fit theevidence container (or a hot plate).5.1.1 An oven is recommended to achieve a constanttemperature throughout the system.1This practice
13、is under the jurisdiction of ASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved Jan. 15, 2016. Published February 2016. Originallyapproved in 1991. Last previous edition approved in 2012 as E1412 12. DOI:10.1520/E
14、1412-16.2For 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.Copyright ASTM International, 100 Barr Harbor Drive,
15、PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 Temperature Measuring DeviceA thermometer orthermocouple capable of measuring temperatures in the rangeof 40 to 100C.5.3 Adsorption Package.5.3.1 Commercial charcoal adsorption packages are avail-able from several companies. These pack
16、ages, in the form ofpolymer strips or small charcoal canisters or “C-bags,” areused to adsorb organic vapors.5.3.1.1 The minimum recommended polymer strip size is 10mm by 10 mm, or 100 mm2.5.3.2 Non-Commercial Adsorption Packages.5.3.2.1 C-BagsPrepare C-bags by encapsulating 0.2 g ofactivated charco
17、al within a folded sheet of high strength, lightweight, high porosity tissue paper, such as that commonly usedfor making tea bags.35.3.3 Storage of Adsorption PackagesTo preventcontamination, store all adsorption packages away from anysources of organic vapors prior to and after sampling.6. Reagents
18、 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 ChemicalSociety where such specifications are available.4O
19、ther 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.6.2 Adsorption Package:6.2.1 C-Bags:6.2.1.1 4 by 5 in. (approximate) high strength, light weight,high porosity filter paper.6.2
20、.1.2 Activated charcoal.6.2.2 Commercial charcoal adsorption package.6.2.3 Check charcoal media purity by, at a minimum,desorbing a representative unit using the same elution solventas will be used for questioned samples and analyzing inaccordance with Test Method E1618.6.3 Elution SolventSuitable e
21、lution solvents are carbondisulfide, n pentane, or diethyl ether. Use of a heavier solvent,such as toluene or tetrachloroethylene, is sometimes necessarywhen the compounds of interest have low molecular weights.6.3.1 Check solvent purity by evaporating to at least twicethe extent used in the analysi
22、s and analyzing the evaporatedsolvent in accordance with Test Method E1618.6.3.2 Read and follow the safety precautions described inthe safety data sheet (SDS) of the extraction solvent that isused.7. Sample Preparation/Adsorption Procedure7.1 Observe the appropriate procedures for handling anddocum
23、entation of all submitted samples as described in Prac-tice E1492.7.1.1 Open and examine the fire debris sample in order todetermine that it is consistent with its description.7.1.1.1 Resolve any discrepancies between the submittingagencys description of the evidence and the analysts obser-vation pr
24、ior to the completion of the report.7.2 Place an adsorbent package in the evidence containeraccording to laboratory protocols and reseal the container.Suspend the adsorbent package above the sample wheneverpossible.7.3 Heat the container to a temperature of 50 to 80C, for 2to 24 h. The longer times
25、or higher temperatures, or both, arerequired for the adsorption of higher boiling point compoundsor for the adsorption of very small quantities of volatilehydrocarbons. The adsorption temperature and duration mayvary based on the sample.3, 57.3.1 When other evidentiary considerations arise (such asd
26、ocument or latent print examinations) it may be appropriate toconduct the adsorption at ambient temperature (approximately20C) for extended periods (24 h or longer) to minimizedamage.7.3.2 Room temperature adsorption may also be appropriateto detect low molecular weight compounds.7.3.3 The optimum a
27、dsorption time for maximum sensitiv-ity will depend on the adsorption package and temperatureselected. Temperatures lower than 60C may be insufficient tovolatilize compounds heavier than C16.7.3.4 Temperatures in excess of 80C may result in dispro-portionate recovery of higher molecular weight compo
28、undswith the displacement of lower molecular weight compounds.7.3.5 The optimum adsorption time for representative sam-pling or maximum sensitivity, or both, will depend on theadsorption package, the adsorption temperature, and the ignit-able liquid composition and concentration.7.3.5.1 Adsorption t
29、imes for routine screening of samplesare typically in the range of 8 to 24 h.7.3.5.2 Data that appears overloaded or excessively dis-placed may be corrected by resampling at ambienttemperatures, or with shortened adsorption times (1 to 4 h), orby performing a solvent extract on a portion of the debr
30、is inaccordance with Practice E1386.7.4 A known amount (typically, 0.1 L to 0.5 L) of aninternal standard may be added to the sample in order toevaluate the efficiency of the procedure.7.4.1 Internal standards are typically prepared using a singlecompound that is easily identified (such as 3-phenylt
31、oluene ordiphenylmethane) dissolved in the eluting solvent.7.4.2 If an internal standard is added, the compound and thequantity added shall be documented along with themanufacturer, grade, and lot number used.3Dietz, W. R., “Improved Charcoal Packaging for Accelerant Recovery byPassive Diffusion,” J
32、ournal of Forensic Sciences, Vol 35, 1991, pp. 111121 (Unk).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
33、 Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.5Newman, R, et al., “The Use of Activated Charcoal Strips for Fire DebrisExtractions by Passive Diffusion. Part 1: The Effects of Time, Temperature, StripSi
34、ze and Sample Concentration,” Journal of Forensic Sciences, Vol 41, 1996, pp.351370.E1412 1627.5 Document the adsorption parameters including the typeand amount of adsorbent used, adsorption temperature andadsorption time.8. Elution Procedure8.1 Remove the adsorption package from the evidencecontain
35、er. If it is not to be eluted immediately, store theadsorption package in a clean, vapor-tight container.8.2 Follow the evidence documentation and handling pro-cedures described in Guide E1459 and Practice E1492.8.3 Place the adsorption substrate in a properly labeledcontainer and desorb with a mini
36、mal amount of eluting solventrequired for instrumental analysis (typically 50 to 1000 L).8.4 Document the type and approximate volume of solventused to desorb the analyte(s) from the adsorbent.9. Sealing9.1 A septum seal or screw cap glass vial may be used forcollecting and sealing the extract for a
37、nalysis.10. Extract and Adsorbent Storage10.1 Refer to Practice E2451 for short term and long termstorage of ignitable liquid extracts.11. Blanks and Standards11.1 Run frequent blanks on each lot of adsorbent packages.11.1.1 Analyze an absorbent package blank by eluting theadsorbent with 50 to 1000
38、L of solvent and analyze accordingto Test Method E1618.11.1.2 Prepare a system blank by placing an adsorbentpackage into a clean dry evidence container and running theadsorbent procedure as described in Section 7. Elute theadsorption package according to Section 8, and analyze theextract according t
39、o Test Method E1618.11.1.2.1 If an internal standard is routinely used, include aninternal standard in the blank.11.2 When necessary, charcoal may be activated andcleaned by heating in a 400C oven for 4 h, then cooling in adesiccator.11.3 Periodically check the adsorption efficiency by runningthis p
40、rocedure on a sample containing a known volume ofstandard ignitable liquid.12. Keywords12.1 activated charcoal; fire debris samples; passive head-space concentrationASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this
41、 standard. Users of this standard are expressly advised 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
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