1、Designation: E2154 15E2154 15aStandard Practice forSeparation and Concentration of Ignitable Liquid Residuesfrom Fire Debris Samples by Passive HeadspaceConcentration with Solid Phase Microextraction (SPME)1This standard is issued under the fixed designation E2154; the number immediately following t
2、he designation indicates the year oforiginal 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
3、 the procedure for removing small quantities of ignitable liquid residues from samples of fire debris.An adsorbent material is used to extract the residue from the static headspace above the sample. Then, analytes are thermallydesorbed in the injection port of the gas chromatograph (GC).1.2 This pra
4、ctice is best suited for screening fire debris samples to assess relative ignitable liquid concentration and forextracting ignitable liquid from aqueous samples.1.3 This practice is suitable for extracting ignitable liquid residues when a high level of sensitivity is required due to a very lowconcen
5、tration of ignitable liquid residues in the sample.1.3.1 Unlike other methods of separation and concentration, this method recovers a minimal amount of the ignitable residuespresent in the evidence, leaving residues that are suitable for subsequent resampling.1.4 Alternate separation and concentrati
6、on procedures are listed in Section 2.1.5 This standard cannot replace knowledge, skill, or ability acquired through appropriate education, training, and experienceand should be used in conjunction with sound professional judgment.1.6 This standard does not purport to address all of the safety conce
7、rns, 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 regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1386 Practice for Separation of Ignitable
8、Liquid Residues from Fire Debris Samples by Solvent ExtractionE1388 Practice for Sampling of Headspace Vapors from Fire Debris SamplesE1412 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by Passive Headspace Concentration WithActivated CharcoalE1413 Practice for Separa
9、tion of Ignitable Liquid Residues from Fire Debris Samples by Dynamic Headspace ConcentrationE1492 Practice for Receiving, Documenting, Storing, and Retrieving Evidence in a Forensic Science LaboratoryE1618 Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromat
10、ography-MassSpectrometry3. Summary of Practice3.1 A fiber coated with a polydimethylsiloxane stationary phase is exposed to the headspace of the fire debris sample containerto extract ignitable liquid residues. The fiber, which is housed in a needle similar to a syringe needle, is introduced directl
11、y in theinjection port of a gas chromatograph to thermally desorb the analytes.4. Significance and Use4.1 This practice is suited ideally for screening samples for the presence, relative concentration, and potential class of ignitableliquid residues in fire debris.1 This practice is under the jurisd
12、iction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved March 1, 2015Sept. 1, 2015. Published April 2015September 2015. Originally approved in 2001. Last previous edition approved in 20082015as E2154 01 (200
13、8).E2154 15. DOI: 10.1520/E2154-15.10.1520/E2154-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This doc
14、ument 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 depict all changes accurately, ASTM recommends that users consult prior editions as
15、 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 19428-2959. United States14.2 This is a very sensitive separation procedure, capab
16、le of isolating small quantities of ignitable liquid residues from a sample,that is, a 0.1 L spike of gasoline on a cellulose wipe inside of a 1-gal can is detectable.4.3 Actual recovery will vary, depending on several factors, including adsorption temperature, container size, competition fromthe sa
17、mple matrix, ignitable liquid class and relative ignitable liquid concentration.4.4 Because this separation takes place in a closed container, the sample remains in approximately the same condition in whichit was submitted. Repeat and interlaboratory analyses, therefore, may be possible. Since the e
18、xtraction is nonexhaustive, thetechnique permits reanalysis of samples.4.5 This practice is intended for use in conjunction with other extraction techniques described in Practices E1386, E1388,E1412, and E1413.4.6 The extract is consumed in the analysis. If a more permanent extract is desired, one o
19、f the separation practices describedin Practices E1386, E1412, or E1413 should be used.5. Apparatus5.1 Heating System, such as, an oven or heating mantle to fit the evidence container (or a hot plate).5.2 Temperature Measuring Device, such as, a thermometer or thermocouple capable of measuring tempe
20、ratures in the rangeof 40 to 110C.5.3 SPME Apparatus, such as, a solid phase microextraction fiber holder.5.4 SPME FiberSeveral polymer coatings can be used to extract volatiles such as ignitable liquid residues. A100 mpolydimethylsiloxane (PDMS) coating has been shown to perform well for most C10-C
21、25 compounds while a 85 m Polyacrylate(PA) and a combined 75 m Carboxen/PDMS has been shown to perform well for C1-C10 compounds (1).35.5 Punch.5.6 Rubber Sleeve Septum.6. Sample Preparation/Analysis Procedure6.1 Observe the appropriate procedures for handling and documentation of all submitted samp
22、les as described in PracticeE1492.6.1.1 Open and examine the fire debris sample to determine that it is consistent with its description.6.1.1.1 Resolve any discrepancies between the submitting agents description of the evidence and the analysts observation withthe submitting agent prior to the compl
23、etion of the report.6.2 Verify that the fiber is free of ignitable residue components and other contaminates by introducing the fiber into the GCunder the injector desorption and chromatographic conditions for ignitable residue analysis. This fiber residue “blank” alwaysshould be evaluated before re
24、sidue sampling when performing a manual injection and desorption.contaminants.6.2.1 Introducing the fiber into the GC under the injector desorption and chromatographic conditions for ignitable residueanalysis. This fiber residue “blank” always should be evaluated before residue sampling when perform
25、ing a manual injection anddesorption.6.2.2 Perform When performing batch runsanalysis of fiber blanks in advance when necessary for autosampler apparatus.forautosampler apparatus, all fibers determined to be clean by analysis should be promptly sealed in a vapor-tight container(s) untilready for use
26、.6.3 If the sample container has a metal lid, make a hole in the lid and install a rubber sleeve septum in the opening.6.4 Heat the container until the sample reaches the desired temperature (approximately 20-30 min, but longer equilibration timesmay be needed depending on the heating method or the
27、amount and type of matrix present in the can, or both).6.4.1 Temperatures lower than 60C may be insufficient to volatilize compounds above C16.6.4.2 Temperatures above 80C may result in a significant discrimination against high volatility compounds when the 100 mPDMS fiber is used.6.5 Remove the con
28、tainer from the heating apparatus.6.6 Immediately puncture the rubber sleeve septum or plastic evidence bag with the needle of the SPME apparatus.6.7 Expose the SPME fiber to the headspace of the container for the desired sampling duration.6.7.1 The optimum exposure time for maximum sensitivity will
29、 depend on the temperature and the concentration andcomposition of the volatile compound present in the sample headspace.6.7.2 Exposure times for routine screening of samples typically are in the range of 5-15 min.3 The boldface numbers in parentheses refer to a list of references at the end of this
30、 standard.E2154 15a26.7.3 Residue extracts that provide off-scale or poorly resolved chromatographic responses should be resampled at lowertemperatures or shorter exposure times.6.8 Secure the fiber in the needle by withdrawing it into the SPME apparatus. Remove the apparatus from the sample contain
31、er.6.8.1 Rubber sleeve septa are self-sealing. Puncture holes in evidence bags should be sealed after sampling.6.9 Desorb the fiber for approximately 1.5 to 4 min at a minimum of 200C and 260C and analyze the Analyze the adsorbateby exposing the fiber in the injection port of a gas chromatograph. De
32、sorb the fiber for approximately 1.5 to 4 min between 200Cand 260C. Analysis is performed as described in Test Method E1618.6.9.1 Some instruments can desorb fibers using an autosampler apparatus. The acceptability of the autosampler parameters shallbe verified using known ignitable liquids and fibe
33、r blanks within a sequence.6.10 A blank shall be run before each sample to ensure thatRepeat each step in Section 6 the fiber is completely desorbed andfree of contaminants. as necessary for each remaining fire debris sample.6.10.1 A blank is run by exposing and analyzing the fiber in the gas chroma
34、tograph under normal operating conditions.Pre-viously analyzed fiber blanks are analyzed during an autosampler sequence. At least one fiber blank must be analyzed, preferablynear the end of the sequence, to verify that fibers were not contaminated during storage or sample processing.6.11 Record the
35、adsorption parameters including the exposure time and temperature in the analytical case notes.7. Blanks and Standards7.1 Analysis of a fiber blank (6.2) is required immediately before each manual sample extraction and batch analysis of fiberblanks prior to sample extractions when using autosampler
36、apparatus.7.1.1 If an internal standard is routinely used, include the internal standard in the blank run by placing the internal standard inan empty container and exposing the SPME fiber as described in Section 6.7.2 Periodically check the adsorption efficiency of the fiber by running this procedur
37、e on a sample containing a known volumeof an ignitable liquid standard.7.3 An ignitable liquid standards library should be maintained with neat and evaporated commonly ignitable liquids recoveredfrom sample containers by this technique at various concentrations.8. Keywords8.1 fire debris samples; pa
38、ssive headspace concentration; solid phase microextraction (SPME)REFERENCES(1) Ren, Q.L., and Bertsch, W.A., “AComprehensive Sample Preparation Scheme forAccelerants in SuspectArson Cases,” Journal of Forensic Science,JFSCA, Vol 44, No. 3, May 1999, pp. 504515.(2) Furton, K.G., Almirall, J.R., and B
39、runa, J., “A Simple, Inexpensive, Rapid, Sensitive and Solventless Technique for the Analysis of Accelerants inFire Debris Based on SPME,” Journal of High Resolution Chromatography, Vol 18, October 1995, pp. 15.(3) Furton, K.G., Almirall, J.R., and Bruna, J., “A Novel Method for the Analysis of Gaso
40、line from Fire Debris Using Headspace Solid PhaseMicroextraction,” Journal of Forensic Science, JFSCA, Vol 41, No. 1, January 1996, pp. 1222.(4) Almirall, J.R., Bruna, J., and Furton, K.G., “The Recovery of Accelerants in Aqueous Samples from Fire Debris Using Solid Phase Microextraction(SPME),” Sci
41、ence and Justice, Journal of the Forensic Science Society, Vol 36, No. 4, 1996, pp. 283287.(5) Almirall, J.R., Wang, J., Lothridge, K., and Furton, K.G., “The Detection and Analysis of Flammable or Combustible Liquid Residues on HumanSkin,” Journal of Forensic Science, JFSCA, Vol 45, No. 2, March 20
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