Title

Ignitable liquid classification and identification using the summed-ion mass spectrum

Authors

Authors

M. E. Sigman; M. R. Williams; J. A. Castelbuono; J. G. Colca;C. D. Clark

Comments

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Abbreviated Journal Title

Instrum. Sci. Technol.

Keywords

identification; ignitable liquid; summed-ion mass spectrum; GAS CHROMATOGRAPHY/MASS SPECTROMETRY; PRINCIPAL COMPONENT ANALYSIS; PIECEWISE ALIGNMENT ALGORITHM; AUTOMOTIVE GASOLINE SAMPLES; RETENTION; TIME ALIGNMENT; CHEMOMETRIC ANALYSIS; FEATURE-SELECTION; FIRE DEBRIS; Chemistry, Analytical; Instruments & Instrumentation

Abstract

The mass spectra calculated by summing the intensities of each nominal mass over all chromatographic times, the summed ion spectra, were calculated for a set of 440 commercially available ignitable liquids that had been analyzed by gas chromatography-mass spectrometry. Each ignitable liquid is generally comprised of a mixture of chemicals, and the mixtures may be very complex in some cases, e.g., petroleum distillates, gasoline, etc. The summed ion spectra were evaluated to determine if they contained sufficient information content to allow their use for rapid and accurate identification of the ignitable liquid in a database or library. The summed ion nominal mass spectra were encoded in one bit per channel at 1% transition intensity and a set of 96,580 unique pairwise comparisons were made between spectra, resulting in an average of approximately 50 differing channels per comparison. A subset of 62 summed ion spectra were further compared by a similarity metric and found by cluster analysis to group closely along the ASTM ignitable liquid classification scheme. Receiver operator characteristic analysis of the use of the similarity index in combination with the summed ion spectra was shown to provide 99% probability of correct liquid identification and 95% probability of correct ASTM classification by primary and sub-class. Interlaboratory tests found 95% probability of correct liquid identification and 85% probability of correct ASTM classification at the primary class level. These results demonstrate the use of the summed ion spectrum as a first step in the rapid identification of an ignitable liquid by database or library searching.

Journal Title

Instrumentation Science & Technology

Volume

36

Issue/Number

4

Publication Date

1-1-2008

Document Type

Article

Language

English

First Page

375

Last Page

393

WOS Identifier

WOS:000257054400004

ISSN

1073-9149

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