Browsing by Subject "total vaporization"

Now showing 1 - 3 of 3
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    Chemical analysis of racing fuels using total vaporization and gas chromatography mass spectrometry (GC/MS)
    (RSC, 2016-05) Bors, Dana; Goodpaster, John V.; Chemistry and Chemical Biology, School of Science
    The National Hot Rod Association (NHRA) is the governing body of North American drag racing. As a supervisory agency, NHRA monitors racing fuels for regulatory purposes and quality control. In this paper, total vaporization and mass spectrometry based methods were developed to analyze nitromethane-based and racing gasoline fuels. Total Vaporization Headspace gas chromatography mass spectrometry (TV-HS-GC/MS) was used to quatitate the amount of methanol in nitromethane fuels to verify that the methanol content was at least 10% (v/v). Total vaporization solid phase microextraction gas chromatography mass spectrometry (TV-SPME-GC/MS) was used to qualitatively identify racing gasoline components, which included isopentane, isooctane, toluene, and tetraethyllead.
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    Optimisation of recovery protocols for double-base smokeless powder residues analysed by total vaporisation (TV) SPME/GC-MS
    (Elsevier, 2016-09) Sauzier, Georgina; Bors, Dana; Ash, Jordan; Goodpaster, John V.; Lewis, Simon W.; Chemistry and Chemical Biology, School of Science
    The investigation of explosive events requires appropriate evidential protocols to recover and preserve residues from the scene. In this study, a central composite design was used to determine statistically validated optimum recovery parameters for double-base smokeless powder residues on steel, analysed using total vaporisation (TV) SPME/GC-MS. It was found that maximum recovery was obtained using isopropanol-wetted swabs stored under refrigerated conditions, then extracted for 15 min into acetone on the same day as sample collection. These parameters were applied to the recovery of post-blast residues deposited on steel witness surfaces following a PVC pipe bomb detonation, resulting in detection of all target components across the majority of samples. Higher overall recoveries were obtained from plates facing the sides of the device, consistent with the point of first failure occurring in the pipe body as observed in previous studies. The methodology employed here may be readily applied to a variety of other explosive compounds, and thus assist in establishing ‘best practice’ procedures for explosive investigations.
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    Optimization of total vaporization solid-phase microextraction (TV-SPME) for the determination of lipid profiles of Phormia regina, a forensically important blow fly species
    (Springer, 2017-11) Kranz, William; Carroll, Clinton; Dixon, Darren; Picard, Christine J.; Goodpaster, John V.; Chemistry and Chemical Biology, School of Science
    A new method has been developed for the determination of fatty acids, sterols, and other lipids which naturally occur within pupae of the blow fly Phormia regina. The method relies upon liquid extraction in non-polar solvent, followed by derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) w/ 1% trimethylchlorsilane (TMCS) carried out inside the sample vial. The analysis is facilitated by total vaporization solid-phase microextraction (TV-SPME), with gas chromatography-mass spectrometry (GC-MS) serving as the instrumentation for analysis. The TV-SPME delivery technique is approximately a factor of five more sensitive than traditional liquid injection, which may alleviate the need for rotary evaporation, reconstitution, collection of high performance liquid chromatography fractions, and many of the other pre-concentration steps that are commonplace in the current literature. Furthermore, the ability to derivatize the liquid extract in a single easy step while increasing sensitivity represents an improvement over current derivatization methods. The most common lipids identified in fly pupae were various saturated and unsaturated fatty acids ranging from lauric acid (12:0) to arachinoic acid (20:4), as well as cholesterol. The concentrations of myristic acid (14:0), palmitelaidic acid (16:2), and palmitoleic acid (16:1) were the most reliable indicators of the age of the pupae.