2022-S-0006 Standard Practice for Gas 

Chromatography Electron Ionization Mass 

Spectrometry Analysis of Ignitable Liquids 

1 

2022-S-0006

Standard Practice for 

Gas Chromatography 

Electron Ionization Mass 

Spectrometry Analysis of 

Ignitable Liquids 

Ignitable Liquids, Explosives & Gunshot Residue Subcommittee

Chemistry: Trace Evidence

Organization of Scientific Area Committees (OSAC) for Forensic Science
2022-S-0006 Standard Practice for Gas 

Chromatography Electron Ionization Mass 

Spectrometry Analysis of Ignitable Liquids 

2 

Draft OSAC Proposed Standard

2022-S-0006 

Standard Practice for Gas 

Chromatography Electron 

Ionization Mass Spectrometry 

Analysis of Ignitable Liquids 

Prepared by 

Ignitable Liquids, Explosives & Gunshot Residue Subcommittee 

Version: 1.0 - OSAC Open Comment 

November 2021 

Disclaimer: 

This OSAC Proposed Standard was written by the Ignitable Liquids, Explosives & Gunshot Residue Subcommittee 

of the Organization of Scientific Area Committees (OSAC) for Forensic Science following a process that includes 

an open comment period. This Proposed Standard will be submitted to a standards developing organization and is 

subject to change. 

There may be references in an OSAC Proposed Standard to other publications under development by OSAC. The 

information in the Proposed Standard, and underlying concepts and methodologies, may be used by the forensicscience community before the completion of such companion publications. 

Any identification of commercial equipment, instruments, or materials in the Proposed Standard is not a 

recommendation or endorsement by the U.S. Government and does not imply that the equipment, instruments, or 

materials are necessarily the best available for the purpose. 

To be placed on the OSAC Registry, certain types of standards first must be reviewed by a Scientific and 

Technical Review Panel (STRP). The STRP process is vital to OSAC’s mission of generating and recognizing 

scientifically sound standards for producing and interpreting forensic science results. The STRP shall provide 

critical and knowledgeable reviews of draft standards or of proposed revisions of standards previously published 

by standards developing organizations (SDOs) to ensure that the published methods that practitioners employ are 

scientifically valid, and the resulting claims are trustworthy. 

The STRP panel will consist of an independent and diverse panel, including subject matter experts, human factors 

scientists, quality assurance personnel, and legal experts, which will be tasked with evaluating the proposed 

standard based on a comprehensive list of science-based criteria. 

For more information about this important process, please visit our website at: https://www.nist.gov/topics/

organization-scientific-area-committees-forensic-science/scientific-technical-review-panels. 
3 

1 Standard Practice for

2 Gas Chromatography Electron Ionization Mass Spectrometry Analysis of 

3 Ignitable Liquids

4 

5 1. Scope

6 1.1 This practice covers the instrumental analysis of ignitable liquids, as well as extracts 

7 from fire debris samples, by gas chromatography-electron ionization mass spectrometry (GC8 MS).

9 1.2 This practice describes performance criteria for use during initial GC-MS method 

10 development and optimization, data evaluation and acceptance criteria, quality assurance and 

11 quality control considerations, and limitations. 

12 1.3 This standard is intended for use by competent forensic science practitioners with the 

13 requisite formal education, discipline-specific training (see Practice E2917), and demonstrated 

14 proficiency to perform forensic casework.

15 1.4 The values stated in SI units are to be regarded as the standard. No other units of 

16 measurement are included in this standard. 

17 1.5 This standard does not purport to address all of the possible safety concerns, if any, 

18 associated with its use. It is the responsibility of the user of this standard to establish 

19 appropriate safety, health, and environmental practices and determine the applicability of 

20 regulatory requirements prior to use. 

21

22 2. Referenced Documents

2.1 ASTM Standards1 23 : 

24 E1386 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by 

25 Solvent Extraction 

26 E1388 Practice for Sampling of Headspace Vapors from Fire Debris Samples

1 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual 

Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.

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27 E1412 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by 

28 Passive Headspace Concentration with Activated Charcoal

29 E1413 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by 

30 Dynamic Headspace Concentration onto an Adsorbent Tube 

31 E(CLASS) Classification for Ignitable Liquids Encountered in Forensic Fire Debris Analysis 

32 E(INTRP) Test Method for Interpretation of Gas Chromatography-Electron Ionization Mass 

33 Spectrometry Data for the Identification of Ignitable Liquid Classes in Forensic Fire 

34 Debris Analysis 

35 E1732 Terminology Relating to Forensic Science 

36 E2154 Practice for Separation and Concentration of Ignitable Liquid Residues from Fire 

37 Debris Samples by Passive Headspace Concentration with Solid Phase Microextraction 

38 (SPME)

39 E2451 Practice for Preserving Ignitable Liquids and Ignitable Liquid Residue Extracts from 

40 Fire Debris Samples

41 WK72631 (E2549 Revision) Practice for Validation and Verification of Analytical Methods 

42 for Forensic Science Service Providers Performing Forensic Chemistry Analysis 

43 E2881 Test Method for Extraction and Derivatization of Vegetable Oils and Fats from Fire 

44 Debris and Liquid Samples with Analysis by Gas Chromatography-Mass Spectrometry

45 E2917 Practice for Forensic Science Practitioner Training, Continuing Education, and 

46 Professional Development Programs 

47 E3189 Practice for Separation of Ignitable Liquid Residues from Fire Debris Samples by 

48 Static Headspace Concentration onto an Adsorbent Tube 

49 E3197 Terminology Relating to Examination of Fire Debris 

50 E3245 Guide for Systematic Approach to the Extraction, Analysis, and Classification of 

51 Ignitable Liquids and Ignitable Liquid Residues in Fire Debris Samples 

52 E3255 Practice for Quality Assurance of Forensic Science Service Providers Performing 

53 Forensic Chemical Analysis

54

55 3. Terminology

56 3.1 Definitions:

57 3.1.1 For definitions of terms that can assist in interpreting this Practice, refer to 

58 Terminology E1732, Terminology E3197, and Classification E(CLASS). 

59 3.2 Definitions of Terms Specific to This Standard: 

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60 3.2.1 analytical batch, n—a set of samples that are analyzed together on the same 

61 instrument; also known as a sample sequence

62 3.2.2 carryover, n—material left over from a previous sample that results in signal that is 

63 observed in the data of a subsequent sample 

64 3.2.3 GC-MS method, n—the complete set of instrument parameters utilized in the 

65 analysis of a test sample.

66 3.3 Abbreviations: 

67 3.3.1 C# – total number of carbon atoms associated with the substitutions on a base 

68 molecule; for example, C3 alkyl benzenes include n-propyl benzene, 3-ethyl toluene, 1,2,4-

69 trimethyl benzene, etc.

70

71 4. Significance and Use

72 4.1 This Practice is useful for generating GC-MS data from ignitable liquids and extracts 

73 from samples suspected to contain ignitable liquid residues. Refer to Guide E3245 for 

74 perspective on the use of GC-MS within the framework of ignitable liquids analysis. Refer to 

75 Practices E1386, E1388, E1412, E1413, E2154, and E3189 for sample preparation procedures. 

76 Refer to Test Method E(INTRP) for interpretation of data generated using this Practice.

77 4.2 This Practice is intended to be used in conjunction with quality assurance procedures 

78 covered in Practice E3255. 

79

80 5. Apparatus

81 5.1 Gas Chromatograph (GC)—A chromatograph capable of using capillary columns and 

82 being interfaced to a mass spectrometer.

83 5.1.1 Sample Inlet System—A sample inlet system that can be operated in either split or 

84 splitless mode with capillary columns.

85 5.1.2 GC Oven—A column oven capable of reproducible temperature program operation 

86 in the range from at least 35 to 300 °C.

87 5.1.3 Column—A capillary, bonded phase, methylsiloxane or phenylmethylsiloxane 

88 column or equivalent. 

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89 5.1.3.1 Alternate column stationary phases can be used for targeted analyses. As an 

90 example, screening for oxygenated compounds could be improved by use of a more polar 

91 column than those listed above. 

92 5.2 Mass Spectrometer (MS)—A mass selective detector capable of acquiring mass spectra 

93 from m/z 10 to m/z 400 with unit resolution or better. 

94 5.3 Data Station—A computerized data station capable of performing the following functions 

95 in conjunction with the GC-MS, either through its operating system or by user programming: 

96 5.3.1 Recording instrument parameters used during sample runs. 

97 5.3.2 Storing time sequenced mass spectral data from sample runs.

98 5.3.3 Retrieving and displaying sample data files. 

99 5.3.4 Generating extracted ion profiles. 

100 5.3.5 Retrieving a specified mass spectrum from a data file and comparing it against one 

101 or more mass spectral libraries.

102 5.3.6 Preparing data presentations in electronic or hard copy format. 

103 5.4 Mass Spectral Library—One or more searchable databases containing mass spectra of 

104 individual chemical compounds. 

105 5.5 Sample introduction devices. 

106 5.5.1 For liquid samples, a syringe capable of introducing a sample size appropriate for 

107 the volume of the inlet upon expansion of the injected solvent. Typical liquid sample sizes 

108 are in the range from 0.1 to 10 microliters. 

109 5.5.2 For vapor samples, a vapor-tight syringe capable of introducing a sample size 

110 appropriate for the volume of the inlet. Typical vapor sample sizes are in the range from 0.5 

111 to 5 milliliters.

112 5.5.3 For some adsorbent tubes (see Practices E1413 and E3189) and for SPME fibers

113 (see Practice E2154), a system capable of desorbing the trapped volatile compounds and 

114 introducing them into the GC-MS.

115

116 6. Chemicals, Reagents, and Reference Materials

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117 6.1 Purity of Reagents—Use reagent grade chemicals or better. Unless otherwise indicated, 

118 it is intended that all reagents conform to the specifications of the Committee on Analytical 

Reagents of the American Chemical Society where such specifications are available. 119 2 Other 

120 grades can be used, provided it is first ascertained that the reagent is of sufficiently high purity to 

121 permit its use without lessening the accuracy of the determination. 

122 6.2 Solvent/Diluent—Use carbon disulfide, diethyl ether, pentane, or other solvent that does 

123 not interfere with the analysis. It is generally desirable to use a solvent whose volatility greatly 

124 exceeds that of most expected solutes to facilitate sample concentration by evaporation, if 

125 necessary. The polarity of the solvent should also be considered. 

126 6.3 Carrier Gas—Use helium or hydrogen of purity 99.995% or higher. 

127 6.4 Test Mixture—Use a test mixture that is suited to the GC-MS method being utilized. 

128 More than one test mixture can be used.

129 6.4.1 The composition of a general-purpose ignitable liquids test mixture at minimum 

130 consists of the following components diluted in solvent: 

131 6.4.1.1 A mixture of alkanes (at least five normal alkanes ranging from n-hexane to n132 eicosane) and aromatic compounds that cover the approximate volatility and polarity 

133 range of the ignitable liquid classes for which the GC-MS method was developed, and 

134 6.4.1.2 At least one pair of closely-eluting compounds, such as isomers or closely135 eluting oxygenates, to facilitate the evaluation of the adequacy of the resolution of the 

136 GC-MS method. 

137 6.4.2 The composition of a targeted test mixture consists of compounds that cover the 

138 volatility range and composition of interest. 

139 6.4.3 Oxygenated compounds can be added to the general-purpose ignitable liquids test 

140 mixture or prepared as a separate targeted test mixture.

141 6.4.4 Examples of suitable test mixtures are listed in Table 1. Refer to Test Method 

142 E2881 for information about test mixtures for use with vegetable-oil based (VOB) products. 

143

2 ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. 

For suggestions on the testing of reagents not listed by the American Chemical Society, see AnalaR Standards for Laboratory Chemicals, BDH Ltd., Poole, 

Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.

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144 Table 1: Examples of possible test mixtures. 

General Purpose Test Mixture

with Oxygenated Compounds

General Purpose Test Mixture

without Oxygenated Compounds

Targeted Test Mixture

for Oxygenated Compounds

Ethanol

Acetone 

2-Propanol (Isopropanol)

2-Butanone

Even-numbered n-alkanes (C6-C20) 

Toluene

p-xylene

1-methyl-2-ethylbenzene

1-methyl-3-ethylbenzene

1,2,4-trimethylbenzene

N-alkanes (C8-C20)

Methylcyclohexane

1-methyl-2-ethylbenzene

1-methyl-3-ethylbenzene

1,3,5-trimethylbenzene

1-methyl-4-ethylbenzene

Ethanol

Acetone

2-Propanol (Isopropanol)

2-Butanone (Methyl ethyl ketone)

145

146 6.5 Reference Ignitable Liquids—Maintain reference ignitable liquids for the various 

147 ignitable liquid classes defined in Table 1 of Practice E(CLASS). 

148 6.5.1 Reference ignitable liquids can be obtained from commercial or retail sources. 

149 Certified ignitable liquid standards are not required. 

150 6.5.2 Assess reference ignitable liquids in accordance with Appendix 2 of Practice E3255

151 prior to use. 

152 7. Instrument Maintenance

153 7.1 Establish and follow an instrument maintenance routine that takes into consideration the 

154 recommendations of the instrument manufacturer and the overall use of the equipment. 

155 7.1.1 Continually evaluate data features to determine if maintenance is necessary to 

156 optimize performance. Data features that can indicate a need for maintenance include 

157 changes in retention time, peak abundance, peak shape, or the presence of unexplainable or 

158 extraneous peaks.

159 7.2 Clean syringes thoroughly with a suitable solvent (see Section 6.2) between injections to 

160 minimize the potential for carryover.

161 7.2.1 Analyzing a solvent blank between samples is recommended but is not required if 

162 studies performed in accordance with Annex A1 demonstrate that the cleaning procedure 

prevents carryover.(1)3 163

3 The boldface numbers in parentheses refer to a list of references at the end of this standard.

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164

165 8. GC-MS Method Development: Performance Criteria and Optimization

166 8.1 Any GC-MS method can be utilized for ignitable liquids analysis, provided it meets the 

167 following performance criteria:

168 8.1.1 All components of interest are eluted. 

169 8.1.1.1 For a general-purpose ignitable liquids GC-MS method, demonstrate that, at a 

170 minimum, light, medium, and heavy range components are present in the total ion 

171 chromatogram (TIC). 

172 NOTE: If light oxygenated compounds (e.g. methanol, ethanol, acetone) are not 

173 included in a general purpose ignitable liquids GC-MS method, develop a 

174 separate targeted GC-MS method for the analysis of these compounds. 

175 8.1.1.2 For a targeted GC-MS method, demonstrate that the compounds of interest are 

176 present in the TIC. 

177 8.1.2 Peak shapes are approximately Gaussian with narrow widths. 

178 8.1.2.1 Gaussian (i.e. symmetrical “bell-shaped”) peaks are ideal; however, some 

179 asymmetry and tailing is normal with temperature gradient programs.(2, 3) 

180 8.1.2.2 Some factors that can affect peak width are column specifications, column 

181 efficiency, temperature program(s), GC flow rate, and sample concentration.(4, 5) 

182 NOTE: Column efficiency is the relationship between a peak's retention time and 

183 its width.(5) Optimum column efficiency for practical performance in ignitable 

184 liquids analysis is that which results in peaks with the shortest retention time that 

185 allows for the desired resolution. 

186 8.1.3 Peak resolution is sufficient for the recognition of patterns associated with the 

187 components of interest, or identification of targeted components. Due to the number of 

188 similar compounds present in ignitable liquids, baseline resolution of all compounds is not 

189 necessary.

190 8.1.3.1 For a general-purpose ignitable liquids GC-MS method, at a minimum, 

191 demonstrate that peak resolution in the C3 and C4 alkyl benzene groups in gasoline, and 

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192 peak resolution in the normal alkanes pattern in diesel fuel, is sufficient for recognition of 

193 key diagnostic features, as discussed in E(CLASS). 

194 8.1.3.2 Adequate peak resolution can usually be achieved through the selection of 

195 appropriate column specifications and gas chromatographic method parameters. 

196 8.1.4 Retention times of components of interest are sufficiently reproducible. 

197 8.1.4.1 For a general-purpose ignitable liquids GC-MS method, at a minimum, 

198 demonstrate that peaks in the light range (e.g. toluene), medium range (e.g. 1,2,4-

199 trimethylbenzene), and heavy range (e.g. n-hexadecane) have sufficiently reproducible 

200 retention times (e.g. no more than the greater value of either ±1% or ±0.1 minute (6) 

201 deviation from the mean value from 10 repetitions performed during the method 

202 development process). 

203 8.1.4.2 For a targeted GC-MS method, at a minimum, demonstrate that the peak for 

204 one compound of interest has sufficiently reproducible retention times (e.g. no more than 

205 the greater value of either ±1% or ±0.1 minute (6) deviation from the mean value from 10 

206 repetitions performed during the method development process). 

207 8.1.5 Mass spectra are collected over one or more mass-to-charge (m/z) ranges which 

208 encompass the relevant ions used for identification of the components of interest. 

209 8.1.5.1 For a general-purpose ignitable liquids GC-MS method, start scans at a m/z 

210 value no greater than 33 for the lower limit, and scan to an upper limit at or greater than a 

211 m/z value of 400. 

212 NOTE: If light oxygenated compounds (e.g. methanol, ethanol, acetone) are 

213 included in a general-purpose ignitable liquids GC-MS method, start scans at a 

214 lower m/z value (e.g. 10). 

215 8.1.6 Relevant ions in the mass spectra of the components of interest are of sufficient 

216 intensity for identification of the components, either by computer library search or by 

217 comparison with reference mass spectra, in accordance with Test Method E(INTRP). 

218 8.1.6.1 Contributions from extraneous ions are minimized in the mass spectra. Some 

219 sources of extraneous ions are column bleed, carrier gas impurities, detector noise, 

220 cleanliness of the mass selective detector, and poor vacuum performance.

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8.1.6.2 Parameters that can affect the intensity of ions in the mass spectra include the 221

222 mass threshold, analog-to-digital (A/D) samples, tune method (e.g. auto tune, standard 

223 spectra tune, etc.), and tune parameters.

224 8.2 Optimize GC-MS methods for sensitivity, to reduce the potential for carryover, and for 

225 run time efficiency while also meeting the performance criteria in 8.1. 

226 8.2.1 Sensitivity can be optimized by adjusting injection, inlet, and detector parameters.

227 8.2.2 Reducing the potential for carryover can be optimized by adjusting injector 

228 parameters or syringe wash parameters, or both, and by running blanks. 

229 8.2.3 Run time efficiency (i.e. minimization of total run time that satisfies performance 

230 criteria) can be optimized by adjusting temperature, flow, and column parameters. 

231 8.3 Examples of GC-MS method parameters for the analysis of samples suspected to contain 

232 ignitable liquids are provided in Appendix 1. 

233

234 9. Sample Preparation, Analysis, and Preservation

235 9.1 Prepare samples in accordance with Section 9 of Guide E3245 in conjunction with one or 

236 more of Practices E1386, E1388, E1412, E1413, E2154, or E3189, as appropriate. 

237 9.2 Analyze the sample by GC-MS.

238 9.2.1 Use an appropriate GC-MS method that has been developed and optimized for use 

239 in ignitable liquids analysis (see Section 8) and validated in accordance with Practice E2549. 

240 9.2.2 Use an appropriate sample introduction device (see Section 5.5) to deliver the 

241 sample to the GC-MS.

242 9.3 When analysis is complete, preserve and store samples according to Practice E2451. 

243

244 10. Data Evaluation and Acceptance Criteria

245 10.1 For all sample types, verify that the sample was properly introduced to the GC-MS, that 

246 the instrument performed correctly, and that data were recorded.

247 10.1.1 Confirm that a TIC and mass spectra were recorded.

248 10.1.2 Evaluate chromatographic features of the TIC. 

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249 10.1.2.1 Confirm that peaks are present in the TIC as appropriate for the sample and 

250 GC-MS method utilized. 

251 NOTE: A blank sample run using a GC-MS method with a solvent delay might 

252 not contain any peaks. 

253 10.1.2.2 Confirm that most peak shapes are approximately Gaussian with narrow

254 widths (see also Section 8.1.2).

255 10.1.2.3 Confirm that the baseline is stable (e.g. with respect to drift, noise, or 

256 spikes). 

257 10.2 For blanks, also confirm that there are no peaks present in the TIC that correspond to 

258 compounds of interest that would interfere with the ability to interpret the data for the presence 

259 of ignitable liquids, in accordance with Test Method E(INTRP). 

260 10.3 For test mixtures, also confirm that retention times for selected peaks are within the 

261 greater value of either ±1% or ±0.1 minute (6) of the retention times established during 

262 development and optimization from previously established values for the GC-MS method used. 

263 10.3.1 A sudden shift of retention times or decrease in abundances could indicate that 

264 instrument maintenance is necessary.

265 10.3.2 If maintenance is conducted that would reasonably be expected to change 

266 retention times (e.g. column trimming or column change) or abundances (e.g. ion source 

267 cleaning), run the test mixture a minimum of three times to determine the new retention times 

268 or abundances to be used for comparison. 

269 10.4 Reject data from samples that do not satisfy the evaluation criteria as follows:

270 10.4.1 For questioned samples, use the criteria in Section 10.1. 

271 10.4.2 For blanks, use the criteria in Sections 10.1 and 10.2. 

272 10.4.3 For test mixtures, use the criteria in Sections 10.1 and 10.3. 

273 10.5 Samples that produce rejected data can be reanalyzed. Additional sample treatment, 

274 such as dilution of overconcentrated samples, can be utilized as needed prior to reanalysis. 

275 10.6 Maintain records of rejected data, any additional sample treatment utilized, and any 

276 reanalysis performed as a portion of the casework documentation. 

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277

278 11. Quality Assurance and Quality Control

279 11.1 Validate or verify GC-MS instruments and GC-MS methods according to Practice 

280 WK72631 and Practice E3255 in order to demonstrate their suitability for use in ignitable liquids 

281 analysis prior to use on unknown samples. 

282 11.1.1 Maintain records of all validations and verifications in accordance with Practice 

283 WK72631 and Practice E3255. 

284 11.2 Tune the mass spectrometer in accordance with manufacturer’s recommendations in 

285 order to ensure correct calibration of mass to charge ratios and to optimize mass spectrometer 

286 system performance.

287 11.2.1 Tune using perfluorotributylamine (PFTBA), or another generally accepted tuning 

288 compound in accordance with manufacturer’s recommendations. 

289 11.2.2 Evaluate tune results against acceptance criteria established in accordance with 

290 manufacturer’s recommendations.

291 11.2.3 Maintain tuning records as a portion of either the quality control documentation or 

292 the casework documentation. 

293 11.3 Analyze at least one process blank per analytical batch in order to demonstrate that 

294 materials such as solvents, adsorption media, glassware, and other sample processing hardware 

295 are free from contaminants that can cause interferences.

296 11.3.1 Use the type of blank appropriate for the phase (i.e. vapor or liquid) of the 

297 questioned sample to be analyzed and, if applicable, to the method used to isolate the 

298 questioned sample from the original fire debris material (see Practices E1388, E1412, E3189, 

299 E1413, E2154, and E1386). 

300 11.3.2 Evaluate the data from blanks according to Sections 10.1 and 10.2. 

301 11.3.3 Maintain data from blanks as a portion of the casework documentation. 

302 11.4 Analyze at least one test mixture at the beginning of each analytical batch in order to 

303 demonstrate proper instrument performance with respect to the components of interest. 

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304 11.4.1 Use a test mixture that is appropriate for the GC-MS method being performed (see 

305 Section 6.4).

306 11.4.2 Evaluate the data from test mixtures to confirm proper instrument performance 

307 according to Sections 10.1 and 10.3. 

308 11.4.3 Maintain data from test mixtures as a portion of the casework documentation or 

309 the quality control documentation, or both. 

310 11.5 Maintain data from reference ignitable liquids that are to be used for the interpretation 

311 of questioned samples and that have been analyzed using the same GC-MS methods as the 

312 questioned samples. 

313

314 12. Limitations

315 12.1 In general, analysis of ignitable liquids by GC-MS is subject to limitations, including 

316 the following:

317 12.1.1 Co-eluting compounds can result in no identification or misidentification. 

318 However, with appropriate GC-MS method development (see Section 8) and the use of 

319 closely eluting compounds in the test mixture (see Section 6.4) the possibility of co-eluting 

320 compounds in ignitable liquids analysis can be minimized. Refer to Test Method E(INTRP)

321 for interpretation of data suspected to contain co-eluting compounds arising from substrate 

322 interferences. 

323 12.1.2 Compounds outside of the approximate volatility and polarity range for which a 

324 specific GC-MS method was developed and optimized might not be observed in the data, or 

325 might not give rise to data that are suitable for comparisons. However, the use of one or 

326 more GC-MS methods developed and optimized to cover the light through heavy range 

327 components of ignitable liquids (see Section 8) can be used to minimize this limitation for

328 the types of compounds that are significant in the interpretation and classification of ignitable 

329 liquids using Test Method E(INTRP).

330 12.1.3 Limited availability of ignitable liquid reference materials or limited searchable 

331 databases can hinder the ability to perform meaningful comparisons. However, the 

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maintenance of appropriate reference ignitable liquids (see Section 6.5) and mass spectral 332

libraries (see Section 5.4) can minimize this limitation. 333

334 13. Keywords

335 13.1 forensic science, fire debris; gas chromatography; ignitable liquid; mass spectrometry

336

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337 ANNEX

338 (Mandatory Information) 

339 A1. CARRYOVER STUDIES

340

341 A1.1. Carryover studies are required when the GC-MS method does not specify the utilization 

342 of analysis of blanks between samples. 

343 A1.2. Carryover studies are performed as part of the GC-MS method validation or verification. 

344 A1.3. Carryover studies are designed to evaluate the potential for carryover when using a 

345 specific GC-MS method over the range of samples anticipated to be encountered during 

346 casework.

347 A1.4. Minimum sample analysis requirements for a carryover study: 

348 A1.4.1 Analyze solvent blanks between samples throughout the entire GC-MS method 

349 validation or verification process. 

350 A1.4.2 Analyze a variety of samples consisting of reference ignitable liquids and matrix 

351 materials, the types and approximate concentrations of which are reflective of those 

352 that are reasonably anticipated to be found in casework scenarios. Include vapors, 

353 liquids, and extracted samples as applicable for the specific GC-MS method to be 

354 utilized. 

355 A1.4.2.1 If the GC-MS method will be utilized for casework samples prepared 

356 using solvent extraction as in Practice E1386, include extracts of samples 

357 consisting of burned matrix materials, vegetable oils, and lubricating oils. 

358 A1.4.2.2 Matrix components routinely encountered as potential interferents (e.g. 

359 styrene) can be analyzed as single compound samples using a reference 

360 material that is fit for purpose for qualitative work, in accordance with 

361 Practice E3255. 

362 A1.4.3 Analyze highly concentrated samples of reference ignitable liquids or single 

363 compounds across the entire volatility range and composition of interest applicable to 

364 the GC-MS method utilized. These samples are deliberately designed to exceed the 

365 reasonable concentrations found in typical casework scenarios, and they are 

366 specifically intended to assess the conditions under which carryover will occur. 

367 A1.5. Evaluate the total ion chromatogram (TIC) and extracted ion profiles (EIPs) of all solvent 

368 blanks for the presence of carryover in the form of peaks which have a signal-to-noise ratio 

369 greater than approximately three times the average local baseline, and that are also observed as a 

370 component of the previous sample. 

371 NOTE: Address peaks not attributable to carryover (e.g. peaks arising from suspected 

372 contamination or siloxane peaks arising from septum bleed) separately within the GC-MS 

373 method validation or verification. 

374 A1.6. Use the information from the evaluation of solvent blanks in Section A1.5 to assess the 

375 risk of carryover during the analysis of routine casework scenarios. 

376

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377 A1.7 Based on the assessment in Section A1.6, implement guidelines for the evaluation of all 

378 casework data for the presence of carryover, as well as mitigation procedures in the event that 

379 carryover is observed in a sample.

380 A1.7.1 When data from a sample does not meet the requirements listed in Sections 8.1.2 

381 through 8.1.4, reanalyze the sample in accordance with Section 10.5, as well as the 

382 subsequent sample(s) in order to mitigate the potential risk of carryover. 

383 A1.8. Maintain all carryover study data and associated documentation as part of the GC-MS 

384 method validation or verification, in accordance with Practice E3255 and WK72631. 

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385 APPENDIX 1

386 (Nonmandatory Information)

387 X1. EXAMPLES OF GC-MS PARAMETERS

388

389 X1.1 Examples of GC-MS methods suitable for the analysis of suspected ignitable liquids are 

390 provided in the table below. 

391 X1.1.1 Method 1 is suitable for the general screening of ignitable liquids, including light 

392 oxygenates. This method can be useful for achieving relatively rapid throughput and narrow 

393 peaks due to its temperature and pressure programs. 

394 X1.1.2 Method 2 is suitable for the general screening of ignitable liquids, but does not scan 

395 for light oxygenates due to the higher start temperature and a delay in initiating the detector. 

396 X1.1.3 Method 3 is suitable for the general screening of ignitable liquids, including light 

397 oxygenates. This method uses a longer column which can enhance resolution; however, peak 

398 shapes are wider and total run time is increased.

399 X1.1.4 Method 4 is suitable for targeted screening only for light oxygenated compounds. 

400 X1.2 Verify instrumental methods prior to use, as these parameters are only intended to serve as 

401 a starting point for method development. 

402

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Spectrometry Analysis of Ignitable Liquids 
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Method 1 Method 2 Method 3 Method 4

Column

 Type 

 Length 

 Inner Diameter

 Film Thickness

HP-1MS 

30 m 

250 μm 

0.25 μm

HP-5MS 

30 m 

250 μm 

0.25 μm

RX-1MS 

60 m 

250 μm 

0.25 μm

HP-1MS 

30 m 

250 μm 

0.25 μm

Injector

 Inlet Temperature

 Injection Volume 

 Split Ratio

290 C 

2 μL 

20:1

250 C 

1 μL 

50:1

250 C 

1 μL 

5:1

290 C 

Manual

20:1

GC

 Mobile Phase 

 Flow Rate

 Temperature

 Program

Helium 

1.8 mL/min 

then 20 

mL/min per 

min to 1.2 

mL/min for 

9.97 min, 

then 20 

mL/min per 

min to 1.8 

mL/min for 0 

min.

40 C hold for 

1.5 min; 

20 C/min to 

140 C, hold 0 

min; 30C/min 

to 300 C, hold 

5.17 min

Helium

1.25 mL/min 

50 C hold for 

3.0min; 

10 C/min to 

280 C, hold for 

4 min

Helium

1 mL/min

hold for 5 

min, then 0.4 

mL/min per 

min to 1.6 

mL/min

40 C hold for 

0 min; 6 

C/min to 80

C, hold 0 min; 

15 C/min to 

250 C, hold 

for 0 min

Helium

0.6 mL/min 

then 20 

mL/min per 

min to 1.2 

mL/min for 

9.97 min, then 

20 mL/min per 

min to 1.8 

mL/min for 0 

min.

35 C hold 4 

min; 10 C/min 

to 100 C, hold 

for 0 min

MS

 Source Temp

 Interface Temp

 Mass Scan Range

 Mass Threshold

 A/D Samples

230 C 

300 C 

14-200 m/z

for 2 min;

14-400 m/z

for 12 min;

14-600 m/z to

end of run

150 

4

230 C 

280 C 

33-400 m/z

150 

4

230 C 

280 C 

10-74 m/z for

5.05 min;

29-450 m/z to

end of run

100 

4

230 C 

290 C 

10-150 m/z

50 

8

Total Run Time 17.003 min 30 min 26 min 10.5 min

403

404

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405 References

406

407 1. Baerncopf, J. & Thomas, S. “Introduction to Fire Debris Analysis” in Forensic Analysis

408 of Fire Debris and Explosives, Evans-Nguyen, K. & Hutches, K., Eds., Springer Nature

409 Switzerland AG 2019, pages 54-55.

410

411 2. Barwick, V.; Langley, J.; Mallet, T.; Stein, B.; Webb, K. “Best Practice Guide for

412 Generating Mass Spectra.” LGC Limited, 2006. ISBN: 978-0-948926-24-2. Available at

413 http://www.rsc.org/images/MS2new_tcm18-102519.pdf (accessed April 8, 2021).

414

415 3. Wahab, M. F.; Patel, D. C.; Armstrong, D. W. “Total Peak Shape Analysis: Detection

416 and Quantitation of Concurrent Fronting, Tailing, and Their Effect on Asymmetry

417 Measurements.” Journal of Chromatography A, 2017, Vol. 1509, pp. 163-170.

418

419 4. Skoog, D.A. and Leary, J.J., Principles of Instrumental Analysis, 4th edition, Harcourt

420 Brace College Publishers, Fort Worth, 1992.

421

422 5. Rood, D., A Practical Guide to the Care, Maintenance, and Troubleshooting of Capillary

423 Gas Chromatographic Systems, 3rd edition, Wiley-VCH, Federal Republic of Germany,

424 1999.

425

426 6. World Anti-Doping Administration (WADA) Technical document of the minimum

427 criteria for chromatographic-mass spectrometric confirmation of the identity of analytes

428 for doping control purposes (2015) (https://www.wada-ama.org/en/resources/science429 medicine/td2015idcr).

2022-S-0006 Standard Practice for Gas 

Chromatography Electron Ionization Mass 

Spectrometry Analysis of Ignitable Liquids