Forensic Chemistry最新文献

Forensic characterization of spontaneous acetone peroxide formation from consumer-aged 2-propanol

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-26 DOI: 10.1016/j.forc.2024.100623

Ryan M. Bain , Andrew Hawkins , Steve Linehan , John R. Stutzman

{"title":"Forensic characterization of spontaneous acetone peroxide formation from consumer-aged 2-propanol","authors":"Ryan M. Bain , Andrew Hawkins , Steve Linehan , John R. Stutzman","doi":"10.1016/j.forc.2024.100623","DOIUrl":"10.1016/j.forc.2024.100623","url":null,"abstract":"<div><div>Numerous instances of well-aged consumer-grade 2-propanol (isopropanol) containing solid primary explosive material have been reported and turned over to the authorities. Herein, one such sample that was turned over to the Bureau of Alcohol, Tobacco, Firearms and Explosives has been analytically characterized to understand the solid primary explosive material as well as the liquid composition for forensic purposes. Upon examination by several analytical methodologies, the liquid phase of the sample contained isopropanol with measurable amounts of species indicative of isopropanol degradation and precursors to triacetone triperoxide. These species included acetone, methanol, acetic acid, isopropyl acetate, hydroxy-propanone, linear acetone peroxides, several atypical linear acetone peroxides species, and cyclic acetone peroxides (<em>e.g.,</em> triacetone triperoxide). The solid material in the container was predominately triacetone triperoxide as well as diacetone diperoxide and tetraacetone tetraperoxide. Microscopic properties and x-ray powder diffractograms of the solid material recovered from the aged isopropanol differed from traditionally synthesized triacetone triperoxide. This comprehensive analysis serves as a reference and aid in analysis for forensic laboratories when alleged samples of spontaneously formed triacetone triperoxide are encountered.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"42 ","pages":"Article 100623"},"PeriodicalIF":2.6,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Application of GC–MS retention index in forensic routine 气相色谱-质谱保留指数在法医常规工作中的应用

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-19 DOI: 10.1016/j.forc.2024.100622

Ettore Ferrari Júnior , Luisa Pereira e Ferreira , Rogério Araújo Lordeiro , Yuri Machado

{"title":"Application of GC–MS retention index in forensic routine","authors":"Ettore Ferrari Júnior , Luisa Pereira e Ferreira , Rogério Araújo Lordeiro , Yuri Machado","doi":"10.1016/j.forc.2024.100622","DOIUrl":"10.1016/j.forc.2024.100622","url":null,"abstract":"<div><div>Gas chromatography–mass spectrometry (GC–MS) is widely used for the identification of substances of forensic interest, but it faces challenges due to the vast diversity of available drugs. In this context, the use of the linear retention index (LRI) can help overcome difficulties associated with the identification of a large number of substances, as it is less susceptible to variations in experimental conditions compared to retention time (RT). Building an LRI database allows rapid and simultaneous identification of several compounds, including new and structurally similar substances, thus standardizing analytical identification. This study aimed to evaluate the use of the retention index (RI) in both intralaboratory and interlaboratory forensic routines. Over a 50-week period on the same GC–MS system, RI values were effectively adjusted by reinjecting an n-alkane mix after maintenance that required vacuum breaks, updating the retention times of each substance evaluated (benzocaine, caffeine, cocaine and flunitrazepam). Interlaboratory reproducibility was evaluated between two forensic laboratories using up to 104 analytes. Two oven temperature programs, three GC brands and two analytical columns were evaluated. Under the same analytical conditions, the ΔRI was ≤10 index units (i.u.) for 103 substances, with testosterone enanthate showing a ΔRI = 11 i.u.. The proposed method proved to be reproducible and selective, and the use of RI has demonstrated accuracy as a complementary technique for identifying a wide range of analytes. Furthermore, the sharing of an RI database can strengthen the analytical routine, being a way to quickly obtain information on the identification of new drugs.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100622"},"PeriodicalIF":2.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Improved differentiation of NPS analogs through the application of chemometric methods to GC-solid deposition-FTIR spectra 通过将化学计量学方法应用于气相色谱-固相沉积-傅立叶变换红外光谱，改进对 NPS 类似物的区分

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-14 DOI: 10.1016/j.forc.2024.100619

Jennifer L. Bonetti , Ruben F. Kranenburg , Stephen Hokanson , Matthew Pothier , Saer Samanipour , Arian C. van Asten

{"title":"Improved differentiation of NPS analogs through the application of chemometric methods to GC-solid deposition-FTIR spectra","authors":"Jennifer L. Bonetti , Ruben F. Kranenburg , Stephen Hokanson , Matthew Pothier , Saer Samanipour , Arian C. van Asten","doi":"10.1016/j.forc.2024.100619","DOIUrl":"10.1016/j.forc.2024.100619","url":null,"abstract":"<div><div>Novel psychoactive substances pose a significant analytical challenge for forensic laboratories. Gas Chromatography with Infrared Spectroscopy (GC-IR) is typically presented as producing visually distinct spectra. However, this is not the case for all compounds. In this study, we showcase three synthetic cathinone analogs (methylone, N-ethylpentylone, and pentylone) which produce extremely visually similar solid state IR spectra.</div><div>A primary dataset of these analogs was generated at the Amsterdam Police Laboratory. Libraries were created using two different sample preparation methods. The same compounds were also analyzed at the Virginia Department of Forensic Science (DFS). It was observed that changes in either instrument or sample preparation were enough to pose challenges to both the visual assessment and a library matching algorithm. Additionally, week-to-week variation was observed within the primary dataset. Principal Component Analysis (PCA) in combination with mahalanobis distances for objective comparison was assessed. A leave-one-sample-out cross validation accurately identified 100% of the samples in the primary dataset.</div><div>This study shows how the application of chemometrics to spectral GC-IR data can substantiate the instrument’s differentiation capabilities and provide valuable objective support for a compound identification. In addition, limitations in the consistency of GC-IR spectra over time and across instruments and sample preparation methods were observed which could affect how the forensic community utilizes these techniques. Specifically, this study shows that shared GC-IR libraries might pose selectivity limitations. Therefore, laboratories must exercise caution if shared/generic GC-IR libraries are utilized for casework, and it is recommended that instrument and solvent specific libraries are generated.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100619"},"PeriodicalIF":2.6,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142704612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development and evaluation of a nontargeted electrochemical surface-enhanced Raman spectroscopy (EC-SERS) screening method applied to forensic seized drug casework samples 开发和评估应用于法医缉获毒品案件样本的非靶向电化学表面增强拉曼光谱（EC-SERS）筛查方法

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-10 DOI: 10.1016/j.forc.2024.100621

Colby E. Ott , Alexis Wilcox , Sharon Kalb , Amber McConnell , Edward Sisco , Luis E. Arroyo

{"title":"Development and evaluation of a nontargeted electrochemical surface-enhanced Raman spectroscopy (EC-SERS) screening method applied to forensic seized drug casework samples","authors":"Colby E. Ott , Alexis Wilcox , Sharon Kalb , Amber McConnell , Edward Sisco , Luis E. Arroyo","doi":"10.1016/j.forc.2024.100621","DOIUrl":"10.1016/j.forc.2024.100621","url":null,"abstract":"<div><div>Screening tests in forensic laboratories are a critical step in ensuring an efficient and effective analytical scheme for presumptive identification. Electrochemical surface-enhanced Raman spectroscopy (EC-SERS) represents a novel workflow that can be applied both in the laboratory and on-site as a fast, inexpensive, and selective approach to seized drug screening. Using cyclic voltammetry and a 785 nm Raman spectrometer, a nontargeted screen was developed using silver screen-printed electrodes and tested on a panel of common drugs of abuse and adulterants. Following characterization of the analyte panel, in-house binary and tertiary mixtures were assessed and the effectiveness of the developed EC-SERS method was tested using common score-based algorithms including correlation, hit-quality-index, spectral angle mapper, and correlation of the 1st derivative. For in-house blind samples, this approach allowed for positive identification of at least one compound in 100 % of samples. Identification of all compounds was lower at 52 %. Seized drug samples from adjudicated casework were tested on-site at the Maryland State Police laboratory as a fit-for-purpose study. EC-SERS provided an accurate screening result of 86 % using the 1st derivative correlation. Applying knowledge of both the local drug landscape and the prevalence of specific adulterants, this value improved to a positive screening of 93 % for the authentic samples. EC-SERS represents a novel approach to drug screening that could impact forensic laboratories, customs and border patrol, public health, and scene investigations. Future work should focus on improved data processing and chemometric tools for data generated in EC-SERS methods.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100621"},"PeriodicalIF":2.6,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Observation of chromatographic differences by non-specialist viewers for one-dimensional gas chromatography and comprehensive two-dimensional gas chromatography output 非专业人员观察一维气相色谱和综合二维气相色谱输出的色谱差异

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-09 DOI: 10.1016/j.forc.2024.100620

Clarissa Camara , Cynthia Cheung , Katelynn A. Perrault Uptmor

{"title":"Observation of chromatographic differences by non-specialist viewers for one-dimensional gas chromatography and comprehensive two-dimensional gas chromatography output","authors":"Clarissa Camara , Cynthia Cheung , Katelynn A. Perrault Uptmor","doi":"10.1016/j.forc.2024.100620","DOIUrl":"10.1016/j.forc.2024.100620","url":null,"abstract":"<div><div>In the context of forensic investigations, chromatography is used to characterize a sample’s components, providing a chemical pattern to compare with known references which is often presented to individuals without specialized training in analytical chemistry. Comprehensive two-dimensional gas chromatography (GC×GC) has recently become popular in forensic research for analyzing samples such as fire debris samples, drugs, chemical threats, human remains detection, and more. New methods are developed in forensic research regularly, which challenge our view of what may be increasingly complex to convey through scientific communication. This study investigated individuals’ ability to observe differences in images for non-chromatographic photographs, one-dimensional gas chromatography (GC) chromatograms, and comprehensive two-dimensional gas chromatography (GC×GC) contour plots. The goal was to identify whether comparative observations between two outputs were facilitated or hindered when observing GC chromatograms compared to GC×GC contour plots, using photographs as a control. Participants indicated low difficulty in finding differences between pairs of images in all categories. They scored highly at indicating when two images were distinguishable or indistinguishable, with no significant difference between control images and each category. These results support that GC×GC output can be implemented in expert testimony without challenges over traditional one-dimensional techniques. Ongoing research should avoid statements that GC×GC may facilitate or hinder juror comprehension, as the results currently indicate no significant benefit or drawback. Additional research is needed to improve understanding of how technique explanation could aid expert witness testimony to better evaluate how this increasingly common technique will fit into future forensic casework opportunities.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100620"},"PeriodicalIF":2.6,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Assessment of two benzylation strategies for the analysis of nerve-agent derived ethyl- and pinacolyl methyl phosphonic acids in sandy loam soil by GC–MS 利用气相色谱-质谱法分析沙质壤土中神经毒剂衍生的乙基和频哪醇甲基膦酸的两种苄基化策略评估

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-06 DOI: 10.1016/j.forc.2024.100616

Vidia A. Gokool , Alexander K. Vu , Saphon Hok , Carlos A. Valdez

{"title":"Assessment of two benzylation strategies for the analysis of nerve-agent derived ethyl- and pinacolyl methyl phosphonic acids in sandy loam soil by GC–MS","authors":"Vidia A. Gokool , Alexander K. Vu , Saphon Hok , Carlos A. Valdez","doi":"10.1016/j.forc.2024.100616","DOIUrl":"10.1016/j.forc.2024.100616","url":null,"abstract":"<div><div>Despite their prohibition by the Chemical Weapons Convention, nerve agents (NAs) remain in use against military and civilian targets. Due to their high reactivity, NAs readily degrade to phosphonic acids, making them important markers in the inspection of areas of presumed NA use. In this work, we assess the use of benzylation to modify ethyl- and pinacolyl methylphosphonic acids, degradation products of VX and Soman respectively, for their efficient detection in a soil matrix at ∼10 and ∼1 μg/g using GC–MS. The soil matrix, Sandy Loam (SL), was chosen for its ubiquitous nature, complex composition with silica particles embedded in clay, and low organic content. In this study, we demonstrate that benzylation via benzyl bromide yields a LOD = 25.6 ng/mL for benzylated-EMPA and LOD = 30.1 ng/mL for benzylated-PMPA. This is superior to the use of p-methoxybenzyl trichloroacetimidate in providing stable phosphonic acid ester derivatives for analysis. A base-modified procedure for <em>p</em>-methoxybenzylation was explored in this study yielding a LOD = 29.1 ng/mL for <em>p</em>-methoxybenzylated-EMPA and LOD = 39.8 ng/mL for <em>p</em>-methoxybenzylated-PMPA. Both benzylation pathways (benzyl bromide and p-methoxybenzyl trichloroacetimidate) can be used to yield phosphonic acid derivatives that provide further confirmation of these Soman and VX degradation products in soil samples in investigative scenarios. The work herein represents the first application of benzylation methods for the analysis of these NA markers in the acidic, silicon-based SL soil.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100616"},"PeriodicalIF":2.6,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Portable near-infrared detection to replace color tests in an analytical scheme for forensic drug identification 在法医鉴定毒品的分析方案中，用便携式近红外检测仪取代颜色检测仪

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-06 DOI: 10.1016/j.forc.2024.100615

Annique van Beek , Laura I. Stuyver , Henk-Jan Ramaker , Emile M. Mes , Arian C. van Asten , Ruben F. Kranenburg

{"title":"Portable near-infrared detection to replace color tests in an analytical scheme for forensic drug identification","authors":"Annique van Beek , Laura I. Stuyver , Henk-Jan Ramaker , Emile M. Mes , Arian C. van Asten , Ruben F. Kranenburg","doi":"10.1016/j.forc.2024.100615","DOIUrl":"10.1016/j.forc.2024.100615","url":null,"abstract":"<div><div>In the ever-changing drug market the popularity and availability of substances is dynamic. In the Netherlands, ketamine and various cathinones have recently seen increased prevalence. It is crucial for law enforcement to quickly obtain an initial indication of the identity of a substance. This first test also serves as quality control for subsequent confirmation with GC–MS analysis. Traditionally, color tests have been used for these purposes. While these tests are quick and inexpensive, they have the disadvantage of reacting only to a few traditional drugs. Suitable color tests are not available for many new psychoactive substances (NPS). Near-infrared (NIR) spectroscopy is a rapid technique that provides a characteristic spectrum for organic compounds. This technique is more versatile than color tests and can adapt more quickly to market changes by incorporating reference spectra into the library. This study demonstrates the feasibility of obtaining a good quality NIR spectrum from a 20 mg sub-sample in a test tube. This was achieved by scanning the test tube through the glass bottom. In the routine analytical scheme, these test tubes were subsequently batchwise analyzed by GC–MS. From the NIR spectra, 84 % true positive and 100 % true negative results were achieved on 516 casework samples, including identification of substances without available color tests like ketamine. Missed false negatives primarily involved new substances absent from the library, emphasizing the need for continuous library updates. NIR’s adaptability to market changes is crucial, allowing the inclusion of new substances as they emerge. This method enhances law enforcement’s ability to make informed decisions, aiding in the indictment process.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100615"},"PeriodicalIF":2.6,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhancing Counterfeit Banknote Analysis: Case Studies Using TOF-SIMS 加强伪钞分析：使用 TOF-SIMS 的案例研究

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-03 DOI: 10.1016/j.forc.2024.100617

Alice Bejjani , Raymond Tannous , Georges Chalhoub , Mazen Hamdan , Bilal Nsouli

引用次数: 0

Halogen-bond mediated charge transfer for visual competitive colorimetric detection of fentanyl 卤素键介导的电荷转移用于芬太尼的视觉竞争性比色检测

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-03 DOI: 10.1016/j.forc.2024.100618

Boyan Li , Qiongyao Ning , Wenyou Ye , Qianxi Wang , Haili Yu , Xuecheng Chen , Yi He

{"title":"Halogen-bond mediated charge transfer for visual competitive colorimetric detection of fentanyl","authors":"Boyan Li , Qiongyao Ning , Wenyou Ye , Qianxi Wang , Haili Yu , Xuecheng Chen , Yi He","doi":"10.1016/j.forc.2024.100618","DOIUrl":"10.1016/j.forc.2024.100618","url":null,"abstract":"<div><div>Colorimetric assays are inexpensive and attractive tools for the detection of fentanyl (FTN), yet further enhancing their sensitivity remains a major challenge. Herein, we develop a halogen-bond mediated visual competitive colorimetric assay for FTN using Erythrosine B (EB) as a probe. The addition of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide (F-127) induces the EB aggregation, strongly suppressing the background signal. Upon the introduction of FTN, the subsequent competitive reaction displaces F-127 to generate EB-FTN charge-transfer complexes via N<sup>…</sup>I halogen bonds between electron-rich amine groups and electron-deficient iodine sites, accompanying a significant absorbance wavelength shift and pink-to-purple color change. The limits of detection of this approach for FTN are 2 mg·L<sup>−1</sup> by the naked eye and 0.19 mg·L<sup>−1</sup> by UV–vis spectroscopy, which are approximately 3.7-fold to 4 orders of magnitude more sensitive than the reported colorimetric assays. Meanwhile, the present method is well applied for FTN-spiked domestic sewage samples, and an easy-to-use smartphone-based digital image colorimetry is also fabricated. It is expected that such an assay can play a key role in alleviating the worldwide opioid overdose crisis.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100618"},"PeriodicalIF":2.6,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Use of optimized 1H selTOCSY for identification and individualization of petrol samples from fire debris 使用优化的 1H selTOCSY 对火灾残骸中的汽油样本进行识别和个性化处理

IF 2.6 3区医学

Forensic Chemistry Pub Date : 2024-11-01 DOI: 10.1016/j.forc.2024.100614

Yanita Yankova , John Warren , Michael D. Cole , Silvia Cirstea

{"title":"Use of optimized 1H selTOCSY for identification and individualization of petrol samples from fire debris","authors":"Yanita Yankova , John Warren , Michael D. Cole , Silvia Cirstea","doi":"10.1016/j.forc.2024.100614","DOIUrl":"10.1016/j.forc.2024.100614","url":null,"abstract":"<div><div>Detection and identification of ignitable liquids in fire investigation is ongoing challenge for forensics investigators. This study uses the analytical power of NMR analysis and permits the identification of trace amounts of olefinic compounds the complex mixture of petrol that aids the individualization of petrol sources. The <sup>1</sup>H selTOCSY NMR method has proven to be successful in the investigation of the four sets of alkenes namely: 3-methyl-1-butene (set 1), a mixture of 3-methyl-1-butene and 1-pentene (set 2), 2-methyl-2-butene (set 3) and a mixture of cis and <em>trans</em>-2-pentene (set 4) in petrol samples evaporated to different extents, simulating the action of weathering of actual casework samples, and still achieved significant discrimination of petrol brands at 25 % and 50 % evaporation. Discrimination of burned samples also proved possible, both of burnt petrol its own and then petrol burned on different substrates including wood, carpet, fabric, and paper materials representing common household fire debris residues. <sup>1</sup>H selTOCSY NMR experiments on these alkene signals remove most of the non-alkene-related signals from the spectra and thus provide additional clarity in heavily burnt and contaminated samples, increasing the capacity to discriminate between samples using the four alkene markers.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"41 ","pages":"Article 100614"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0