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Karen L. Wahl - One of the best experts on this subject based on the ideXlab platform.
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integration of stable isotope and trace contaminant concentration for enhanced forensic Acetone discrimination
Talanta, 2013Co-Authors: James J Moran, Christopher J Ehrhardt, Helen W. Kreuzer, Jon H. Wahl, Karen L. WahlAbstract:We analyzed 21 neat Acetone samples from 15 different suppliers to demonstrate the utility of a coupled stable isotope and trace contaminant strategy for distinguishing forensically-relevant samples. By combining these two pieces of orthogonal data we could discriminate all of the Acetones that were produced by the 15 different suppliers. Using stable isotope ratios alone, we were able to distinguish 8 Acetone samples, while the remaining 13 fell into four clusters with highly similar signatures. Adding trace chemical contaminant information enhanced discrimination to 13 individual Acetones with three residual clusters. The Acetones within each cluster shared a common manufacturer and might, therefore, not be expected to be resolved. The data presented here demonstrates the power of combining orthogonal data sets to enhance sample fingerprinting and highlights the role disparate data could play in future forensic investigations.
P. Jedlovszky - One of the best experts on this subject based on the ideXlab platform.
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Detailed insight into the hydrogen bonding interactions in Acetone-methanol mixtures. A molecular dynamics simulation and Voronoi polyhedra analysis study
Physical Chemistry Chemical Physics, 2012Co-Authors: A. Idrissi, K. Polok, W. Gadomski, I. Vyalov, A. Agapov, M. Kiselev, M. Barj, P. JedlovszkyAbstract:Voronoi polyhedra (VP) analysis of mixtures of Acetone and methanol is reported on the basis of molecular dynamics computer simulations, performed at 300 K and 1 bar. The composition of the systems investigated covers the entire range from neat Acetone to neat methanol. Distribution of the volume, reciprocal volume and asphericity parameter of the VP as well as that of the area of the individual VP faces and of the radius of the empty voids located between the molecules are calculated. To investigate the tendency of the like molecules to self-associate the analyses are repeated by disregarding one of the two components. The self-aggregates of the disregarded component thus turn into large empty voids, which are easily detectable in VP analysis. The obtained results reveal that both molecules show self-association, but this behavior is considerably stronger among the Acetone than among the methanol molecules. The strongest self-association of the Acetone and methanol molecules is found in their mole fraction ranges of 02-0.5 and 0.5-0.6, respectively. The caging effect around the methanol molecules is found to be stronger than around Acetones. Finally, the local environment of the Acetone molecules turns out to be more spherical than that of the methanols, not only in the respective neat liquids, but also in their mixtures.
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Can existing models qualitatively describe the mixing behavior of Acetone with water?
Journal of Chemical Physics, 2009Co-Authors: P. Jedlovszky, A. Idrissi, G. JancsoAbstract:The Helmholtz free energy of neat water, neat Acetone, and Acetone-water mixtures of various compositions covering the Acetone mole fraction range of 0.02-0.26 is calculated at 300 K by computer simulation using the method of thermodynamic integration. In the calculations the mixtures of Kirkwood-Buff force field (KBFF) Acetone with both TIP4P and SPC/E water are considered. The Helmholtz free energy of mixing calculated from the free energy difference of the mixture and of the two neat phases is found to be positive at each composition considered, indicating that the studied systems are thermodynamically unstable. The range of immiscibility is estimated to extend from the Acetone mole fraction value below 0.01 to about 0.28 for both model pairs. Since a previous investigation [A. Perera and F. Sokolić, J. Chem. Phys. 121, 11272 (2004)] showed that, with the exception of SPC/E water and KBFF Acetone, Acetone-water model pairs exhibit demixing behavior, the present result points out that currently no existing Acetone model can qualitatively reproduce the phase behavior of Acetone-water mixtures, i.e., the well known experimental fact that Acetone is miscible with water in any proportion.
James J Moran - One of the best experts on this subject based on the ideXlab platform.
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integration of stable isotope and trace contaminant concentration for enhanced forensic Acetone discrimination
Talanta, 2013Co-Authors: James J Moran, Christopher J Ehrhardt, Helen W. Kreuzer, Jon H. Wahl, Karen L. WahlAbstract:We analyzed 21 neat Acetone samples from 15 different suppliers to demonstrate the utility of a coupled stable isotope and trace contaminant strategy for distinguishing forensically-relevant samples. By combining these two pieces of orthogonal data we could discriminate all of the Acetones that were produced by the 15 different suppliers. Using stable isotope ratios alone, we were able to distinguish 8 Acetone samples, while the remaining 13 fell into four clusters with highly similar signatures. Adding trace chemical contaminant information enhanced discrimination to 13 individual Acetones with three residual clusters. The Acetones within each cluster shared a common manufacturer and might, therefore, not be expected to be resolved. The data presented here demonstrates the power of combining orthogonal data sets to enhance sample fingerprinting and highlights the role disparate data could play in future forensic investigations.
Masayuki Ikeda - One of the best experts on this subject based on the ideXlab platform.
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Curvi-linear relation between Acetone in breathing zone air and Acetone in urine among workers exposed to Acetone vapor.
Toxicology letters, 1992Co-Authors: Toshio Kawai, Tomojiro Yasugi, Kazunori Mizunuma, Shun'ichi Horiguchi, Hiroshi Iguchi, Masayuki IkedaAbstract:An occupational health study was conducted on 45 Acetone-exposed male workers in combination with 343 non-exposed men to examine the quantitative relationship between the intensity of Acetone vapor exposure and the concentration of Acetone in urine. The time-weighted average Acetone concentrations were measured by means of diffusive samplers with water as absorbent, whereas urine samples were collected at the end of the shift as well as before the shift on the next morning. Acetone concentration in shift-end urine did not increase when the workers were exposed to Acetone up to approx. 15 ppm, and this was followed by a gradual increase at a higher atmospheric Acetone concentration, in a manner dependent to Acetone vapor concentration. The comparison in Acetone concentrations between the urine samples collected at the shift-end and those before the shift of the next morning showed that the levels in two sets of samples were the same among those exposed to 15 or less ppm Acetone, whereas Acetone in the shift-end samples was significantly higher than the counterpart levels in the pre-shift samples among those exposed to Acetone at more than 15 ppm.
J. Williams - One of the best experts on this subject based on the ideXlab platform.
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On the relationship between Acetone and carbon monoxide in different air masses
Atmospheric Chemistry and Physics, 2003Co-Authors: M. De Reus, H. Fischer, F. Arnold, J. De Gouw, R. Holzinger, C. Warneke, J. WilliamsAbstract:Carbon monoxide and Acetone measurements are presented for five aircraft measurement campaigns at mid-latitudes, polar and tropical regions in the northern hemisphere. Throughout all campaigns, free tropospheric air masses, which were influenced by anthropogenic emissions, showed a similar linear relation between Acetone and CO, with a slope of 21-25 pptv Acetone/ppbv CO. Measurements in the anthropogenically influenced marine boundary layer revealed a slope of 13-16 pptv Acetone/ppbv CO. The different slopes observed in the marine boundary layer and the free troposphere indicate that Acetone is emitted by the ocean in relatively clean air masses and taken up by the ocean in polluted air masses. In the lowermost stratosphere, a good correlation between Acetone and CO was observed as well, however, with a much smaller slope (~5 pptv Acetone/ppbv CO) compared to the troposphere. This is caused by the longer photochemical lifetime of CO compared to Acetone in the lower stratosphere, due to the increasing photolytic loss of Acetone and the decreasing OH concentration with altitude. No significant correlation between Acetone and CO was observed over the tropical rain forest due to the large direct and indirect biogenic emissions of Acetone. The common slopes of the linear Acetone-CO relation in various layers of the atmosphere, during five field experiments, makes them useful for model calculations. Often a single observation of the Acetone-CO correlation, determined from stratospheric measurements, has been used in box model applications. This study shows that different slopes have to be considered for marine boundary layer, free tropospheric and stratospheric air masses, and that the Acetone-CO relation cannot be used for air masses which are strongly influenced by biogenic emissions.
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On the relationship between Acetone and carbon monoxide in air masses of different origin
Atmospheric Chemistry and Physics Discussions, 2003Co-Authors: M. De Reus, H. Fischer, F. Arnold, J. De Gouw, R. Holzinger, C. Warneke, J. WilliamsAbstract:Carbon monoxide and Acetone measurements are presented for five aircraft measurement campaigns at mid-latitudes, polar and tropical regions in the northern hemisphere. Throughout all campaigns, free tropospheric air masses, which were influenced by anthropogenic emissions, showed a similar linear relation between CO and Acetone, with a slope of 21?25 pptv Acetone/ppbv CO. Measurements in the anthropogenically influenced marine boundary layer revealed a slope of 13?16 pptv Acetone/ppbv CO. The different slopes observed in the marine boundary layer and the free troposphere indicate that Acetone is emitted by the ocean in relatively clean air masses and taken up by the ocean in polluted air masses. In the lowermost stratosphere, a good correlation between CO and Acetone was observed as well, however, with a much smaller slope (~5 pptv Acetone/ppbv CO) compared to the troposphere. This is caused by the longer photochemical lifetime of CO compared to Acetone in the lower stratosphere, due to the increasing photolytic loss of Acetone and the decreasing OH concentration with altitude. No significant correlation between CO and Acetone was observed over the tropical rain forest due to the large direct and indirect biogenic emissions of Acetone. The common slopes of the linear Acetone-CO relation in various layers of the atmosphere, during five field experiments, makes them useful for model calculations. Often a single observation of the CO-Acetone correlation, determined from stratospheric measurements, has been used in box model applications. This study shows that different slopes have to be considered for marine boundary layer, free tropospheric and stratospheric air masses, and that the CO-Acetone relation cannot be used for air masses which are strongly influenced by biogenic emissions.