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Ho Manh L, Chen VCP, Rosenberger J, Wang S, Yang Y, Schug KA. Prediction of Vacuum Ultraviolet/Ultraviolet Gas-Phase Absorption Spectra Using Molecular Feature Representations and Machine Learning. J Chem Inf Model 2024; 64:5547-5556. [PMID: 38938209 DOI: 10.1021/acs.jcim.4c00676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Ultraviolet (UV) absorption spectroscopy is a widely used tool for quantitative and qualitative analyses of chemical compounds. In the gas phase, vacuum UV (VUV) and UV absorption spectra are specific and diagnostic for many small molecules. An accurate prediction of VUV/UV absorption spectra can aid the characterization of new or unknown molecules in areas such as fuels, forensics, and pharmaceutical research. An alternative to quantum chemical spectral prediction is the use of artificial intelligence. Here, different molecular feature representation techniques were used and developed to encode chemical structures for testing three machine learning models to predict gas-phase VUV/UV absorption spectra. Structure data files (.sdf) and VUV/UV absorption spectra for 1397 volatile and semivolatile chemical compounds were used to train and test the models. New molecular features (termed ABOCH) were introduced to better capture pi-bonding, aromaticity, and halogenation. The incorporation of these new features benefited spectral prediction and demonstrated superior performance compared to computationally intensive molecular-based deep learning methods. Of the machine learning methods, the use of a Random Forest regressor returned the best accuracy score with the shortest training time. The developed machine learning prediction model also outperformed spectral predictions based on the time-dependent density functional theory.
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Affiliation(s)
- Linh Ho Manh
- Department of Industrial, Manufacturing, and Systems Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Victoria C P Chen
- Department of Industrial, Manufacturing, and Systems Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Jay Rosenberger
- Department of Industrial, Manufacturing, and Systems Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Shouyi Wang
- Department of Industrial, Manufacturing, and Systems Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Yujing Yang
- Department of Industrial, Manufacturing, and Systems Engineering, The University of Texas at Arlington, Arlington, Texas 76019, United States
| | - Kevin A Schug
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, Texas 76019, United States
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Sharma B, Gadi R. Analytical Tools and Methods for Explosive Analysis in Forensics: A Critical Review. Crit Rev Anal Chem 2023:1-27. [PMID: 37934616 DOI: 10.1080/10408347.2023.2274927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
This review summarizes (i) compositions and types of improvised explosive devices; (ii) the process of collection, extraction and analysis of explosive evidence encountered in explosive and related cases; (iii) inter-comparison of analytical techniques; (iv) the challenges and prospects of explosive detection technology. The highlights of this study include extensive information regarding the National & International standards specified by USEPA, ASTM, and so on, for explosives detection. The holistic development of analytical tools for explosive analysis ranging from conventional methods to advanced analytical tools is also covered in this article. The most important aspect of this review is to make forensic scientists familiar with the challenges during explosive analysis and the steps to avoid them. The problems during analysis can be analyte-based, that is, interferences due to matrix or added molding/stabilizing agents, trace amount of parent explosives in post-blast samples and many more. Others are techniques-based challenges viz. specificity, selectivity, and sensitivity of the technique. Thus, it has become a primary concern to adopt rapid, field deployable, and highly sensitive techniques.
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Affiliation(s)
- Bhumika Sharma
- Department of Applied Sciences & Humanities, Indira Gandhi Delhi Technical University for Women, Delhi, India
| | - Ranu Gadi
- Department of Applied Sciences & Humanities, Indira Gandhi Delhi Technical University for Women, Delhi, India
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Klapec DJ, Czarnopys G, Pannuto J. Interpol review of the analysis and detection of explosives and explosives residues. Forensic Sci Int Synerg 2023; 6:100298. [PMID: 36685733 PMCID: PMC9845958 DOI: 10.1016/j.fsisyn.2022.100298] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Douglas J. Klapec
- Arson and Explosives Section I, United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
| | - Greg Czarnopys
- Forensic Services, United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
| | - Julie Pannuto
- United States Department of Justice, Bureau of Alcohol, Tobacco, Firearms and Explosives, Forensic Science Laboratory, 6000 Ammendale Road, Ammendale, MD, 20705, USA
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Reavis M, Goodpaster J. Quantitative analysis of smokeless powder particles in post‐blast debris via gas chromatography/vacuum ultraviolet spectroscopy (
GC
/
VUV
). J Forensic Sci 2022; 67:1431-1440. [PMID: 35368092 PMCID: PMC9322668 DOI: 10.1111/1556-4029.15037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/05/2022] [Accepted: 03/21/2022] [Indexed: 11/29/2022]
Abstract
Forensic analysis of smokeless powder particles recovered from the debris of an improvised explosive device can provide information about the type of smokeless powder used and can aid investigation efforts. In this study, quantitative methods were used to yield information about the difference in the chemical composition of the particles pre‐ and post‐blast. The technique, gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV), was able to quantify nitroglycerin, 2,4‐dinitrotoluene, diphenylamine, ethyl centralite, and di‐n‐butyl phthalate in pre‐ and post‐blast smokeless powder particles using heptadecane as an internal standard. Post‐blast debris was obtained via controlled explosions with assistance from the Indiana State Police Bomb Squad. Two galvanized steel and two polyvinyl chloride pipe bombs were assembled. Two devices contained single‐base smokeless powder and two contained double‐base smokeless powder. 2,4‐dinitrotoluene and diphenylamine were successfully quantified in the single‐base smokeless powder post‐blast debris while nitroglycerin, diphenylamine, and ethyl centralite were successfully quantified in the double‐base smokeless powder post‐blast debris. Compounds were detected at concentrations as low as 9 μg of 2,4‐dinitrotoluene per mg, <3 μg of diphenylamine per mg, 131 μg of nitroglycerin per mg, and <3 μg of ethyl centralite per mg. Concentration changes between pre‐ and post‐blast smokeless powder particles were determined as well as microscopic differences between pre‐ and post‐blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives.
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Affiliation(s)
- Madison Reavis
- Forensic and Investigative Sciences Department Indiana University—Purdue University Indianapolis Indianapolis Indiana USA
| | - John Goodpaster
- Forensic and Investigative Sciences Department Indiana University—Purdue University Indianapolis Indianapolis Indiana USA
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Ge K, Hu Y, Zheng Y, Jiang P, Li G. Aptamer/derivatization-based surface-enhanced Raman scattering membrane assembly for selective analysis of melamine and formaldehyde in migration of melamine kitchenware. Talanta 2021; 235:122743. [PMID: 34517611 DOI: 10.1016/j.talanta.2021.122743] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/18/2022]
Abstract
The analysis of contaminants in migration of food contact material (FCMs) is an urgent demand for food safety. In this study, melamine and formaldehyde in melamine kitchenware were selectively analyzed by surface-enhanced Raman scattering (SERS) via aptamer/derivatization-based membrane assembly. The membrane assembly was designed by simple filtration of Ag nanoparticles-decorated "stellate" silicon dioxide (SiO2/Ag) and composites of reduced graphene oxide and Ag nanoparticles (rGO/Ag) functioned with specific reagents. High selectivity can be realized by melamine aptamer and derivatization reagent of formaldehyde, respectively. The relative standard deviations (RSDs) of melamine and formaldehyde analysis for 11 replicate measurements, 14 consecutive days and 25 batches are less than 6.0 %, which shows excellent repeatability and reproducibility. After the method was validated, the limits of detection (LOD) for melamine and formaldehyde are 0.15 mg/L and 0.21 mg/L, respectively. The developed method was applied to determine the content of melamine and formaldehyde in migration of melamine kitchenware with low relative errors (less than 5.3 %) compared to chromatographic results. The recoveries of melamine and formaldehyde for migrations of melamine kitchenware are 91.2-110.0 % and 94.0-106.0 % with RSDs in range of 1.8-8.3 % and 4.7-9.1 %, respectively. The method proposed a new concept of convenient, portable and reliable strategy for analysis of melamine and formaldehyde in migration from FCMs.
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Affiliation(s)
- Kun Ge
- School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yuling Hu
- School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China.
| | - Yanjie Zheng
- Shenzhen Academy of Metrology and Quality Inspection, 518055, Shenzhen, China
| | - Peichun Jiang
- Shenzhen Academy of Metrology and Quality Inspection, 518055, Shenzhen, China
| | - Gongke Li
- School of Chemistry, Sun Yat-sen University, Guangzhou, 510275, China.
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Cruse CA, Goodpaster JV. Optimization of gas chromatography/vacuum ultraviolet (GC/VUV) spectroscopy for explosive compounds and application to post-blast debris. Forensic Chem 2021. [DOI: 10.1016/j.forc.2021.100362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Cruse CA, Goodpaster JV. A systematic study of the absorbance of the nitro functional group in the vacuum UV region. Anal Chim Acta 2021; 1185:339042. [PMID: 34711315 DOI: 10.1016/j.aca.2021.339042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 11/25/2022]
Abstract
The nitro functional group (NO2) features strongly in compounds such as explosives, pharmaceuticals, and fragrances. However, its gas phase absorbance characteristics in the vacuum UV region (120-200 nm) have not been systematically studied. Gas chromatography/vacuum UV spectroscopy (GC/VUV) was utilized to study the gas phase VUV spectra of various nitrated compounds (e.g., nitrate esters (-R-O-NO2), nitramines (R-N-NO2), nitroaromatics (Ar-NO2), and nitroalkanes (R-NO2)). The nitro absorption maximum appeared over a wide range (170-270 nm) and its wavelength and intensity were highly dependent upon the structure of the rest of the molecule. For example, the nitroalkanes exhibited a trend in that the ratio of the relative absorption intensity between these two absorption features between the alkyl group (<150 nm) and the nitro group (200 nm) increases as the molecular weight increases. It was observed that the addition of multiple nitro functional groups on benzene or toluene resulted in an increase in intensity and blue shift from approximately 240 nm-210 nm. Nitrate esters exhibited an absorption between 170 nm and 210 nm and absorbance increased with increasing nitrogen content. The relative diversity of the spectra obtained was analyzed by Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA). These calculations revealed that the spectra of all the compounds analyzed could be reliably differentiated without any misclassifications.
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Affiliation(s)
- Courtney A Cruse
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street LD326, Indianapolis, IN, 46202, United States
| | - John V Goodpaster
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street LD326, Indianapolis, IN, 46202, United States; Forensic and Investigative Sciences Program, Indiana University-Purdue University Indianapolis (IUPUI), 402 North Blackford Street LD326, Indianapolis, IN, 46202, United States.
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