ThP21



Code: ThP21 Time Slot/Poster Number: 023 Session: Forensics/Geoscience/Environmental Applications

Behavior of Semi-volatile Particles under a Laser and Electron Beam – Influence on the Quality of Analytical Results
Anna Worobiec2; Sanja Potgieter-Vermaak1; Larysa Darchuk2; Herman Potgieter1; Rene Van Grieken2; Vladimir Vishnyakov1
1Manchester Metropolitan University, Manchester, United Kingdom; 2University of Antwerp, Antwerp, Belgium

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Summary
The combination of scanning electron microscopy (SEM) equipped with the energy dispersive X-ray detection (EDX) and micro-Raman spectrometry (MRS) for environmental research can give detailed information about individual atmospheric particles. It is very important to not only examine the fundamental analytical requirements of the individual techniques, but also the characteristic behaviour during measurement. One of the main aspects, which needs be taken into account during the analysis of individual particles by combined SEM-EDX/MRS, is particle damage and any subsequent molecular changes that might occur. It is vital that modifications induced by the analytical method employed, be properly understood and controlled.

Code: ThP21 Time Slot/Poster Number: 024 Session: Forensics/Geoscience/Environmental Applications

Conformational Stability Determination From Raman Spectra Of Ethylisocyanate and Cyclopropylisocyanate
Sarah Xiaohua Zhou; James Durig
University of Missouri-Kansas City, Kansas City, MO

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Summary
Raman and infrared spectra of the gaseous, liquid and/or solid ethylisocyanate and cycloproylisocyanate as well as variable temperature studies of the spectra in liquid xenon and/or liquid krypton have been recorded. Conformational stabilities have been determined, the stable conformer for ethylisocyanate is the cis form and for the cyclopropyl the trans form. These spectroscopic studies have been supported by ab initio calculations from which optimized geometries, conformational stabilities, harmonic force fields, infrared intensities, Raman activities and depolarization ratios have been obtained.

Code: ThP21 Time Slot/Poster Number: 025 Session: Forensics/Geoscience/Environmental Applications

The Influence of Intracellular Storage Material on Bacterial Identification by means of Raman Spectroscopy
Valerian Ciobota1; Eva-Maria Burkhardt2; Wilm Schumacher1; Petra Roesch1; Kirsten Kuesel2; Juergen Popp1, 3
1Institute of Physical Chemistry, Jena, Germany; 2Institute of Ecology, Jena, Germany; 3Institute of Photonic Technology, Jena, Germany

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Summary
The most common energy storage polymer produced by bacteria is polyhydroxybutyrate (PHB). Since PHB can be accumulated in high amounts within the bacterial cells, it is expected that the Raman signals from the above mentioned substance partially or totally overlap the bands from others cell components. Therefore, a study focused on the effects of PHB on the bacterial identification rates is required. In our study six strains belonging to five species were investigated. The identification results obtained by means of support vector machines demonstrate that identification of microorganisms which accumulate PHB is achievable. However, some limitations exist.

Code: ThP21 Time Slot/Poster Number: 026 Session: Forensics/Geoscience/Environmental Applications

Forensic examination of multi-layer white paint by lateral scanning Raman spectroscopy
Samantha Stewart; Steven Bell
Queen's University Belfast, Belfast, United Kingdom

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Summary
Typically for the forensic scientist, discriminating multi-layer white paint is often very difficult or impossible using existing techniques. In this work lateral scanning Raman spectroscopy was successfully utilised to characterize the layer structure of multi-layer paint chips and providing more information than optical techniques in the process.

Code: ThP21 Time Slot/Poster Number: 027 Session: Forensics/Geoscience/Environmental Applications

Foliar Lead Uptake by Lettuce Exposed to Atmospheric Fallouts: Raman Imaging Study
Sophie Sobanska1; Gaëlle Uzu2; Myriam Moreau1; Marie Choël1; Camille Dumat2
1Université de Lille 1, LASIR UMR CNRS 8516, Villeneuve D'ascq, France; 2Université de Toulouse, INPT, UPS, Ecolab, ENSAT, Castanet-Tolosan, France

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Summary
The present work focuses on the molecular characterization and Raman imaging of the Pb rich areas observed in the leaf surface, in order to better understand the mechanism involved in the foliar transfer of atmospheric Pb rich fallouts at the leaf scale.

Code: ThP21 Time Slot/Poster Number: 028 Session: Forensics/Geoscience/Environmental Applications

Quantitative Model Based on Raman Spectra to Evaluate Contaminants in Crack (Cocaine)
Ciro Penido; Marcos T. T. Pacheco; Landulfo Silveira, Jr.
Universidade Camilo Castelo Branco, Sao Jose Dos Campos, Brazil

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Summary
Dscrimination between different types of drugs of abuse and purity analysis of these drugs is of vital importance to the public security and forensics in order to check the veracity of the sample. Raman spectroscopy was used to detect the adulteration in crack. Dilutions of 70% crack in lidocaine, sodium carbonate, benzocaine and caffeine were prepared and submitted to Raman spectroscopy. Principal components analysis scores were used to develop a quantitative model (regression) to correlate the amount of drug in the mixture. Results showed that, for binary mixtures, the PCA scores could detect the amount of crack with low error.

Code: ThP21 Time Slot/Poster Number: 029 Session: Forensics/Geoscience/Environmental Applications

Differential Raman Cross-Section of Dimethyl Sulfide
Robert Barletta; Christopher Roe
Department of Chemistry, Univ. of South Alabama, Mobile, AL

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Summary
Biogenic sulfur compounds such as dimethyl sulfide (DMS) are important contributors to the global carbon cycle. The relative differential Raman cross-section of gas-phase DMS, σDMS, has been measured with visible (Ar-ion laser) and ultraviolet (KrF–laser) excitation in order to assess the applicability of Raman for the direct, quantitative measurement of this compound.

Code: ThP21 Time Slot/Poster Number: 030 Session: Forensics/Geoscience/Environmental Applications

Detection of Arsenobetaine: A Step Towards SERS-based Arsenic Speciation
Danmar Gloria; Grainne Moran; D Brynn Hibbert
University of New South Wales, Unsw, AUSTRALIA

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Summary
This work presents a SERS sensor for measuring the concentration of arsenobetaine as a step towards the development of a system that will be able to speciate arsenic. A SERS substrate was fabricated from polycrystalline gold using an optimized electrochemical oxidation-reduction cycle technique. The substrate was functionalized with 3-mercaptopropionic acid to selectively bind cationic arsenobetaine. The sensor was calibrated between 1 µg kg-1 and 100 mg kg-1 using leave-one-out partial-least squares.

Code: ThP21 Time Slot/Poster Number: 031 Session: Forensics/Geoscience/Environmental Applications

Comparison of Absolute Raman Cross Sections of Explosives in the Solid State and in Solution
Erik Emmons; Augustus Fountain; Steven Christesen; Jason Guicheteau
U.S. Army Edgewood Chemical Biological Center, Apg, MD

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Summary
Due to the increased threat of attack by improvised explisve device, the U.S. Army is interested in developing standoff techniques for detecting traces of explosives on surfaces. Raman spectroscopy is a potentially valuable technique in this regard, but suffers from signal levels that are generally quite low. In order to better quantify these levels, absolute Raman cross sections of explosives in the solid state and in solution have been measured. Variations in the spectra and cross sections in the different phases are discussed.

Code: ThP21 Time Slot/Poster Number: 032 Session: Forensics/Geoscience/Environmental Applications

Analysis of air pollution aerosols by Raman Spectroscopy and spectral resolution methods
Yasmina Dellaa1; Rahmoune Chaabane2; Jacky Kister1; Nathalie Dupuy1
1laboratoire systèmes chimiques complexes, Marseille, France; 2Ecotoxicology and Abiotic stress laboratory, Constantine, Algeria

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Summary
By their physical and chemical properties, carbonates and sulfates, produced by the cement industry, are one of the most important classes of atmospheric aerosols. They can have an impact on ecosystems, health and process of atmospheric chemistry and an important role in global climate change. In the study of this pollution, the confocal Raman microscopy use has a great interest for the characterization of cement dusts collected on aerial parts of plants. Coupled with chemometric data processing, it allows determining particulate heterogeneous components in dust. The study of their effects on metabolic changes was also investigated in this work.

Code: ThP21 Time Slot/Poster Number: 033 Session: Forensics/Geoscience/Environmental Applications

Micro Raman spectroscopy investigation of patinas formed by exposure of copper to vapor of several aqueous electrolyte solutions.
Lucia Noda; Carolina Vautier-Giongo; Caue Moreira; Norberto Gonçalves; Daniel Rettori
Universidade Federal de São Paulo, Diadema, Brazil

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Summary
Patina is a thin layer of corrosion, naturally formed when copper or alloys of copper are exposed to the environment over time. Artificial patinas obtained by the exposition of copper sheets to the vapor from electrolytic aqueous solutions of NaCl, acetic acid, hydrogen chloride and acetic acid plus NaCl, were characterized by micro Raman spectroscopy. The compound formed in patinas obtained from vapor of acetic acid or acetic acid plus NaCl solutions was copper acetate. Patinas obtained from HCl solution are made of atacamite and cuprite and the ones obtained from NaCl solution are made of cuprite.

Code: ThP21 Time Slot/Poster Number: 034 Session: Forensics/Geoscience/Environmental Applications

Composition Of aerosols From The Shelter Of The Chernobyl Power Plant
Larysa Darchuk1; Anna Worobiec1; Victor Krasov2; Valeryi Khan2; Rene Van Grieken1
1University of Antwerp, Antwerp, Belgium; 2Institute for Problems of SNPP, Chornobyl, Ukraine

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Summary
The goal of the investigation was to study the indoor aerosol composition from a room with the nuclear fuel lava. Single particles were collected by Berner cascade impactor. Molecular analysis of the samples was provided by a micro-Raman spectrometer (Renishaw in via, GB) with laser excitation at 785 nm. Raman spectra of more than half of the analyzed particles consist of bands assigned to organic substances. Raman bands typical for uranium oxide, haematite, chalcocite were detected as a composition of the collected single particles.

Code: ThP21 Time Slot/Poster Number: 035 Session: Forensics/Geoscience/Environmental Applications

A Study of Silica Coated Phosphors for Latent Fingerprint Visualisation
Alexander Reip; Robert Withnall; Jack Silver
Brunel University, Uxbridge, UNITED KINGDOM

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Summary
Past research has shown the success of using europium doped yttria for increasing the detection of fingerprints and that work has been built upon by us to improve the powders’ affinities for fingerprints by modifying the surfaces of the phosphors while making sure the modifications do not hinder the luminescent properties of the phosphors.

Code: ThP21 Time Slot/Poster Number: 036 Session: Forensics/Geoscience/Environmental Applications

Metrics for Raman Spectra Identification
Samar Guharay
MITRE, Mclean, VA

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Summary
The unique signature of Raman spectra for different molecules is examined by several approaches including estimation of the root-mean squared error, weighted cross-correlation average and Earth Mover's Distance. A set of identity matching scores, i.e., metrics, is generated from this analysis to quantify the level of uniqueness. The relative strengths of different metrics are systematically analyzed for a variety of analyte molecules. These metrics can be effectively utilized for analysis of Raman spectra and have relevance to many applications including security and forensic screening.