Study of chemical modifications in acidified ignitable liquids analysed by GC–MS

Martín-Alberca, Carlos; García-Ruiz, Carmen; Delémont, Olivier

doi:10.1016/j.scijus.2015.06.006

Cited by 9 publications

(25 citation statements)

References 14 publications

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“…In addition, fire debris analysis is complicated due to many other reasons: the destructive nature of the fire, the high temperatures reached at the scene that usually evaporate almost all of the liquids, the use of foams and water by the firefighters [1,2], or the degradation phenomena, such as weathering or biodegradation that the samples can suffer after the fire [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…The use of chemometric tools, in particular, pattern recognition techniques in order to obtain useful information of the total data matrix has been increased in the last years. The most commonly chemometric tools that are used are principal component analysis (PCA), cluster analysis (CA), discriminant analysis (DA), qualitative data analysis (QDA), or soft independent modelling by class analogy (SIMCA) [4,8,20,21].…”

Section: Introductionmentioning

confidence: 99%

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Application of Headspace Gas Chromatography-Ion Mobility Spectrometry for the Determination of Ignitable Liquids from Fire Debris

et al. 2018

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Abstract:A fast and correct identification of ignitable liquid residues in fire debris investigation is of high importance in forensic research. Advanced fast analytical methods combined with chemometric tools are usually applied for these purposes. In the present study, the Headspace Gas Chromatography-Ion Mobility Spectrometry (HS-GC-IMS) combined with chemometrics is proposed as a promising technique for the identification of ignitable liquid residues in fire debris samples. Fire debris samples were created in the laboratory, according to the Destructive Distillation Method for Burning that is provided by the Bureau of Forensic Fire and Explosives. Four different substrates (pine wood, cork, paper, and cotton sheet) and four ignitable liquids of dissimilar composition (gasoline, diesel, ethanol, and paraffin) were used to create the fire debris. The Total Ion Current (TIC) Chromatogram combined with different chemometric tools (hierarchical cluster analysis and linear discriminant analysis) allowed for a full discrimination between samples that were burned with and without ignitable liquids. Additionally, a good identification (95% correct discrimination) for the specific ignitable liquid residues in the samples was achieved. Based on these results, the chromatographic data from HS-GC-IMS have been demonstrated to be very useful for the identification and discrimination of ignitable liquids residues. The main advantages of this approach vs. traditional methodology are that no sample manipulation or solvent is required; it is also faster, cheaper, and easy to use for routine analyses.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of Headspace Gas Chromatography-Ion Mobility Spectrometry for the Determination of Ignitable Liquids from Fire Debris

et al. 2018

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“…Based on the chemical composition of petroleum fuels, one would expect reaction with sulfuric acid to cause a variety of chemical changes in fuel due to reactions between the sulfuric acid and native compounds in the fuel [2][3][4]. Gasoline fuel exhibits substantial chemical changes due to the presence of tert-butylating compounds, such as methyl tert-butyl ether (MTBE), while the changes to diesel fuel are more subtle, limited to the aromatic moiety of the fuel [2,4]. For the purposes of forensic classification of acid altered diesel fuel, it is necessary to better understand the chemical compositional changes that occur and which may differentiate unaltered from altered fuels.…”

Section: Introductionmentioning

confidence: 99%

Chemical characterization of the acid alteration of diesel fuel: Non-targeted analysis by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry with tile-based Fisher ratio and combinatorial threshold determination

Parsons

Pinkerton

Wright

et al. 2016

Journal of Chromatography A

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The illicit chemical alteration of petroleum fuels is of keen interest, particularly to regulatory agencies that set fuel specifications, or taxes/credits based on those specifications. One type of alteration is the reaction of diesel fuel with concentrated sulfuric acid. Such reactions are known to subtly alter the chemical composition of the fuel, particularly the aromatic species native to the fuel. Comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) is well suited for the analysis of diesel fuel, but may provide the analyst with an overwhelming amount of data, particularly in sample-class comparison experiments comprised of many samples. Tile-based Fisher-ratio (F-ratio) analysis reduces the abundance of data in a GC×GC-TOFMS experiment to only the peaks which significantly distinguish the unaltered and acid altered sample classes. Three samples of diesel fuel from differently branded filling stations were each altered to discover chemical features, i.e., analyte peaks, which were consistently changed by the acid reaction. Using different fuels prioritizes the discovery of features likely to be robust to the variation present between fuel samples and may consequently be useful in determining whether an unknown sample has been acid altered. The subsequent analysis confirmed that aromatic species are removed by the acid alteration, with the degree of removal consistent with predicted reactivity toward electrophilic aromatic sulfonation. Additionally, we observed that alkenes and alkynes were also removed from the fuel, and that sulfur dioxide or compounds that degrade to sulfur dioxide are generated by the acid alteration. In addition to applying the previously reported tile-based F-ratio method, this report also expands null distribution analysis to algorithmically determine an F-ratio threshold to confidently select only the features which are sufficiently class-distinguishing. When applied to the acid alteration of diesel fuel, the suggested per-hit F-ratio threshold was 12.4, which is predicted to maintain the false discovery rate (FDR) below 0.1%. Using this F-ratio threshold, 107 of the 3362 preliminary hits were deemed significantly changing due to the acid alteration, with the number of false positives estimated to be about 3. Validation of the F-ratio analysis was performed using an additional three fuels.

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“…The most popular IID is the classic Molotov cocktail [5], which consist of a glass bottle filled with IL and a wick that is lighted just before being hurled. An advanced and more dangerous version of this device is the chemical ignition Molotov cocktail (CIMC) [6][7][8]. CIMCs are usually closed glass bottles containing gasoline or diesel fuel and concentrated sulfuric acid [5,7].…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the color of the glass represents a challenge due to the fluorescence originated from some surface materials [20]. Additionally, it should be considered that chemical modifications are produced over time in the gasoline and diesel fuel due the presence of sulfuric acid [8]. Therefore, in this work, compounds present in IIDs were measured in different glass bottles to assess if the container features hamper the Raman measurements.…”

Section: Introductionmentioning

confidence: 99%

Analysis of pre-ignited improvised incendiary devices using portable Raman

Martín-Alberca

Lopez‐López

García-Ruiz

2015

Talanta

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Study of chemical modifications in acidified ignitable liquids analysed by GC–MS

Cited by 9 publications

References 14 publications

Application of Headspace Gas Chromatography-Ion Mobility Spectrometry for the Determination of Ignitable Liquids from Fire Debris

Application of Headspace Gas Chromatography-Ion Mobility Spectrometry for the Determination of Ignitable Liquids from Fire Debris

Chemical characterization of the acid alteration of diesel fuel: Non-targeted analysis by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry with tile-based Fisher ratio and combinatorial threshold determination

Analysis of pre-ignited improvised incendiary devices using portable Raman

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