1、Designation: E1618 14Standard Test Method forIgnitable Liquid Residues in Extracts from Fire DebrisSamples by Gas Chromatography-Mass Spectrometry1This standard is issued under the fixed designation E1618; the number immediately following the designation indicates the year oforiginal adoption or, in
2、 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 test method covers the identification of residues ofignitable liquids in extra
3、cts from fire debris samples. Extrac-tion procedures are described in the referenced documents.1.2 Although this test method is suitable for all samples, itis especially appropriate for extracts that contain high back-ground levels of substrate materials or pyrolysis and combus-tion products. This t
4、est method is also suitable for the identi-fication of single compounds, simple mixtures, or non-petroleum based ignitable liquids.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This practice cannot replace knowledge, s
5、kill, or abilityacquired through appropriate education, training, and experi-ence and should be used in conjunction with sound profes-sional judgment.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
6、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:2E1386 Practice for Separation of Ignitable Liquid Residuesfrom Fire Debris Samples by Solvent ExtractionE1388 Practice for
7、 Sampling of Headspace Vapors from FireDebris SamplesE1412 Practice for Separation of Ignitable Liquid Residuesfrom Fire Debris Samples by Passive Headspace Concen-tration With Activated CharcoalE1413 Practice for Separation of Ignitable Liquid Residuesfrom Fire Debris Samples by Dynamic Headspace C
8、on-centrationE2154 Practice for Separation and Concentration of Ignit-able Liquid Residues from Fire Debris Samples by Pas-sive Headspace Concentration with Solid Phase Microex-traction (SPME)E2451 Practice for Preserving Ignitable Liquids and Ignit-able Liquid Residue Extracts from Fire Debris Samp
9、les3. Summary of Test Method3.1 The sample is analyzed with a gas chromatograph (GC)which is interfaced to a mass spectrometer (MS) and a datasystem (DS) capable of storing and manipulating chromato-graphic and mass spectral data.3.2 Post-run data analysis generates extracted ion profiles(mass chrom
10、atograms) characteristic of the chemical com-pound types commonly found in ignitable liquids.Additionally,specific chemical components (target compounds) may beidentified by their mass spectra and retention times. Semi-quantitative determination of target compounds which areidentified by mass spectr
11、a and retention time may be used todevelop target compound chromatograms (TCCs).3.2.1 The total ion chromatogram (TIC), extracted ionprofiles (EIP) for the alkane, alkene, alcohol, aromatic,cycloalkane, ester, ketone and polynuclear aromatic compoundtypes, or TCCs, or combination thereof, are evalua
12、ted by visualpattern matching against known reference ignitable liquids.3.2.2 Ignitable liquids may be grouped into one of sevenmajor classifications or one miscellaneous class, as describedin this test method.4. Significance and Use4.1 The identification of an ignitable liquid residue insamples fro
13、m a fire scene can support the field investigatorsopinion regarding the origin, fuel load, and incendiary natureof the fire.4.1.1 The identification of an ignitable liquid residue in afire scene does not necessarily lead to the conclusion that a firewas incendiary in nature. Further investigation ma
14、y reveal alegitimate reason for the presence of ignitable liquid residues.1This test method is under the jurisdiction ofASTM Committee E30 on ForensicSciences and is the direct responsibility of Subcommittee E30.01 on Criminalistics.Current edition approved July 1, 2014. Published July 2014. Origina
15、lly approvedin 1994. Last previous edition approved in 2011 as E1618 11. DOI: 10.1520/E1618-14.2For 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 Documen
16、t Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.2 Because of the volatility of ignitable liquids andvariations in sampling techniques, the absence of detectablequantities of ignitable liquid resid
17、ues does not necessarily leadto the conclusion that ignitable liquids were not present at thefire scene.4.2 Materials normally found in a building, upon exposureto the heat of a fire, will form pyrolysis and combustionproducts. Extracted ion profiling and target compound identi-fication techniques d
18、escribed herein may facilitate the identi-fication of an ignitable liquid in the extract by reducinginterference by components generated as products of pyrolysis.5. Apparatus5.1 Gas ChromatographA chromatograph capable of us-ing capillary columns and being interfaced to a mass spectrom-eter.5.1.1 Sa
19、mple Inlet SystemA sample inlet system that canbe operated in either split or splitless mode with capillarycolumns; the inlet system may use on-column technology.5.1.2 ColumnAcapillary, bonded phase, methylsilicone orphenylmethylsilicone column or equivalent. Any columnlength or temperature program
20、conditions may be used pro-vided that each component of the test mixture (see 6.4)isadequately separated.5.1.3 GC OvenA column oven capable of reproducibletemperature program operation in the range from 50 to 300C.5.2 Mass SpectrometerCapable of acquiring mass spectrafrom m/z 40 to m/z 400 with unit
21、 resolution or better, withcontinuous data output. Values above m/z 40 may not besufficient to detect or identify some lower molecular weightcompounds; for example, methanol, ethanol, acetone.5.2.1 SensitivityThe system shall be capable of detectingeach component of the test mixture (see 6.4) and pr
22、ovidingsufficient ion intensity data to identify each component, eitherby computer library search or by comparison with referencespectra.5.3 Data StationA computerized data station, capable ofstoring time sequenced mass spectral data from sample runs.5.3.1 Data HandlingThe data system shall be capab
23、le ofperforming, either through its operating system or by userprogramming, various data handling functions, including inputand storage of sample data files, generation of extracted ionprofiles, searching data files for selected compounds, andqualitative and semi-quantitative compound analysis.5.3.2
24、 Mass Spectral LibrariesThe system shall be capableof retrieving a specified mass spectrum from a data file andcomparing it against a library of mass spectra available to thedata system. This capability is considered an aid to the analyst,who will use it in conjunction with chromatographic data andk
25、nown reference materials to identify unknown components.5.4 Syringes:5.4.1 For liquid samples, a syringe capable of introducing asample size in the range from 0.1 to 10.0 L.5.4.2 For gas samples, a gas-tight syringe capable ofintroducing a sample size in the range of 0.5 to 5 mL.6. Chemicals, Reagen
26、ts, and Reference 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
27、 available. Other 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 Solvent/DiluentCarbon disulfide, diethyl ether,pentane, or other solvent that will not interfere with theanaly
28、sis. It is generally desirable to use a solvent whosevolatility greatly exceeds that of the solute to facilitate sampleconcentration by evaporation, if necessary.6.2.1 Use of a heavier solvent, such as toluene ortetrachloroethylene, is sometimes necessary when the com-pounds of interest have low mol
29、ecular weights.6.3 Carrier GasHelium or hydrogen of purity 99.995 %or higher.6.4 Test MixtureThe test mixture shall consist of a mini-mum of the even-numbered normal alkanes (ranging fromn-octane through n-eicosane), methylbenzene (toluene), 1,4-dimethylbenzene (p-xylene), 1-methyl-2-ethylbenzene (o
30、-ethyltoluene), 1-methyl-3-ethylbenzene (m-ethyltoluene), and1,2,4-trimethylbenzene (pseudocumene). Additional com-pounds may be included at the discretion of the analyst. Thefinal test solution is prepared by diluting the above mixturesuch that the concentration of each component is 0.005 %volume/v
31、olume (0.05 microliters/milliliter) in the chosen sol-vent (see 6.2). A typical chromatogram of the test mixture isshown in Fig. 1.6.5 Reference Ignitable LiquidsIgnitable liquids shall beavailable for the various ignitable liquids represented in Table1.6.5.1 Typically, reference ignitable liquids a
32、re diluted1:1000 in an appropriate solvent. Depending on the columncapacity and injection technique, ignitable liquid solutions canbe made somewhat more concentrated to ensure detection ofminor compounds.6.5.2 Certified ignitable liquid standards are not necessary.Most reference ignitable liquids ca
33、n be obtained from com-mercial and retail sources.7. Equipment Calibration and Maintenance7.1 Verify the consistent performance of the chromato-graphic instrument by using blanks and known concentrationsof either prepared test mixture or other known ignitable liquids.Optimize gas flows periodically.
34、7.2 Tune and calibrate mass spectrometer.7.2.1 Tune the mass spectrometer using perfluorotribu-tylamine (PFTBA), or another appropriate calibration standard,according to the instrument manufacturers specifications,prior to use. This should be done at least every day that theinstrument is used or per
35、 manufacturers recommendations.7.2.2 Maintain tuning documentation as a portion of thequality control documentation.E1618 1427.3 Cleaning the equipment.7.3.1 Change septa and clean or replace injector liners on aperiodic basis to avoid sample contamination by carryover ofresidual material from previ
36、ous sample injections.8. Sample Handling Procedure8.1 Only samples of appropriate dilution should be analyzedon a GC-MS system.8.2 Methods for isolating ignitable liquid residues from firedebris for analysis by this test method are described inPractices E1386, E1388, E1412, E1413, and E2154.8.3 Beca
37、use of the volatility of solvents and analytes, caremust be taken to ensure that samples do not evaporate orotherwise change composition prior to analysis. Septum sealvials may be used for short term storage of any solvents orextracts. See Annex A1 for sample and extract storage guid-ance.8.3.1 Avoi
38、d the use of water as a sealant.8.4 Analyze solvent blanks at least once each day that theinstrument is used; maintain these analysis records. This willverify the purity of the solvent and potentially detect carryoveror contamination.FIG. 1 Test Mixture Containing C8-C20 Normal Hydrocarbons, toluene
39、, p-xylene, o-ethyltoluene, m-ethyltoluene, and 1,2,4-trimethylbenzeneTABLE 1 Ignitable Liquid Classification SchemeAClass Light (C4-C9) Medium (C8-C13) Heavy (C9-C20+)Gasoline-all brands,including gasohol and E85Fresh gasoline is typically in the range C4-C12Petroleum Distillates(including De-Aroma
40、tized)Petroleum EtherSome Cigarette Lighter FluidsSome Camping FuelsSome Charcoal StartersBSome Paint ThinnersSome Dry Cleaning SolventsKeroseneDiesel FuelSome Jet FuelsSome Charcoal StartersIsoparaffinic ProductsAviation GasSome Specialty SolventsSome Charcoal StartersSome Paint ThinnersSome Copier
41、 TonersSome Commercial SpecialtySolventsAromatic ProductsSome Paint and VarnishRemoversSome Automotive Parts CleanersXylenes, Toluene-based products.Some Automotive Parts CleanersSpecialty Cleaning SolventsSome Insecticide VehiclesFuel AdditivesSome InsecticideVehiclesIndustrial CleaningSolventsNaph
42、thenic- Paraffinic ProductsCyclohexane basedsolvents/productsSome Charcoal StartersSome Insecticide VehiclesSome Lamp OilsSome InsecticideVehiclesSome Lamp OilsIndustrial SolventsNormal-Alkanes ProductsSolventsPentaneHexaneHeptaneSome Candle OilsSome Copier TonersSome Candle OilsCarbonless FormsSome
43、 Copier TonersOxygenated SolventsAlcoholsKetonesSome Lacquer ThinnersFuel AdditivesSurface Preparation SolventsSome Lacquer ThinnersSome Industrial SolventsMetal Cleaners/Gloss RemoversOthers-MiscellaneousSingle Component ProductsSome Blended ProductsSome Enamel ReducersTurpentine ProductsSome Blend
44、ed ProductsSome Specialty ProductsSome Blended ProductsSome Specialty ProductsAThe products listed in the various classes of Table 1 are examples of known commercial uses of these ignitable liquids. These examples are not intended to beall-inclusive. Reference literature materials may be used to pro
45、vide more specific examples of each classification.BMany of the examples can be prefaced by the word “some,” as in “some charcoal starters.”E1618 1438.5 Clean syringes thoroughly between injections to ensureno carryover.8.5.1 Conduct carryover studies periodically, and maintainrecords that demonstra
46、te the adequacy of laboratory proceduresto prevent carryover.8.5.2 Running a solvent blank between samples is recom-mended but is not necessary if studies demonstrate that thecleaning procedure is adequate to prevent carryover.8.6 Maintain reference files of known ignitable liquids thathave been ana
47、lyzed in the same manner as the questionedsamples.8.7 Chromatogram EvaluationAn adequate chromato-gram with sufficient data for comparison work is one in whichthe peaks of interest are 50 to 100 % of full scale. Re-print thechromatogram, using different parameters (amplitude or pre-sentation of data
48、) to achieve an adequately scaled chromato-gram in the targeted area of investigation.9. Data Analysis9.1 Initial data analysis consists of a visual comparison ofthe total ion chromatograms to reference ignitable liquidchromatograms as described below.9.1.1 The essential requirement for making a cla
49、ssificationusing this procedure is the matching of the sample chromato-gram with a reference ignitable liquid chromatogram obtainedunder similar conditions, noting points of correlation or simi-larities. Make all comparisons using adequate chromatogramsas described in 8.7 and interpretation criteria described inSection 11, Interpretation of Results.9.1.2 The use of externally generated libraries of chromato-grams is not sufficient for identification of an ignitable liquid.Such libraries are intended only to give guidance for selectionof reference ignitable liqu
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