Forensic Chemistry最新文献_第5页

Characterization and classification of organic gunshot residue from neat smokeless powder, cartridge cases, and the hands of known shooters 从干净的无烟火药、弹壳和已知射手的手中提取的有机射击残留物的特征和分类

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-07-01 DOI: 10.1016/j.forc.2025.100683

Thomas D. Ledergerber , Liliana Barbosa , Kourtney Dalzell , Luis Arroyo , Tatiana Trejos

This study encompasses the detection, characterization, and classification of organic gunshot residue (OGSR) through the analysis of three forensically relevant sample types, including neat smokeless powders recovered from live ammunition, extracts from fired cartridge cases, and the hands of known shooters. Liquid chromatography-tandem mass spectrometry is used as an analytical tool for five manufacturer-grade ammunition brands. The relative detection and quantification of Akardite II, ethyl centralite, methyl centralite, diphenylamine, 2-nitrodiphenylamine, and 4-nitrodiphenylamine is used for chemical characterization and to reveal main chemical changes during deflagration. Classification via discriminant analysis methods is effective for neat smokeless powders and spent cartridge cases, reaching correct classification rates as high as 83.7 %. Alternative chemometric techniques, including k-nearest neighbors and support vector machine algorithms, are more appropriate for residues recovered from the shooter's hands that exhibit greater inter-sample variability. The more challenging traces of hand residues yield correct classification rates of up to 62.7 %, partly due to significant changes in the formation of nitro-diphenylamines and Akardite II in some organic gunshot residue. The findings presented in this study demonstrate that analyzing OGSR can offer valuable insights into the discrimination of manufacturer-spent cartridges and, to some extent, hand residues, assisting in forensic investigations and shooting reconstructions when limited evidence is available.

本研究通过对三种法医相关样本类型的分析，包括从实弹中回收的纯无烟粉末、从发射的弹壳中提取的提取物和已知射手的手，包括有机射击残留物（OGSR）的检测、表征和分类。液相色谱-串联质谱法被用作五个制造级弹药品牌的分析工具。通过对赤铁矿、乙基中心石、甲基中心石、二苯胺、2-硝基二苯胺、4-硝基二苯胺的相对检测和定量，进行化学表征，揭示爆燃过程中的主要化学变化。判别分析方法对纯无烟火药和废药筒分类有效，分类正确率高达83.7%。替代化学计量学技术，包括k近邻和支持向量机算法，更适合从枪手的手上恢复残留物，表现出更大的样本间可变性。更具有挑战性的手残留物的正确分类率高达62.7%，部分原因是一些有机枪击残留物中硝基二苯胺和Akardite II的形成发生了重大变化。本研究的发现表明，分析OGSR可以为制造商使用的弹药的歧视提供有价值的见解，在某种程度上，手残留物，在证据有限的情况下，协助法医调查和射击重建。

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引用次数: 0

Development and comparison of reversed-phase ultra high-performance liquid chromatography (RP-UHPLC) and hydrophilic interaction liquid chromatography (HILIC) approaches to the analysis of regioisomeric fluorofentanyl derivatives and related compounds 反相高效液相色谱法（RP-UHPLC）与亲水性相互作用液相色谱法（HILIC）在氟芬太尼区域异构体衍生物及相关化合物分析中的应用及比较

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-29 DOI: 10.1016/j.forc.2025.100682

Jennifer K. Field , Benjamin S. Barrett , Erika Sitch , Ryan E. Mewis , William H. Campbell , Melvin R. Euerby , Oliver B. Sutcliffe

This study describes the development and comparison of low, intermediate and high pH gradient RP-UHPLC-MS/MS with that of gradient HILIC-MS/MS analysis for a range of fluorofentanyl derivatives including four families of ortho-, meta- and para-regioisomers. High pH RP-UHPLC-MS/MS using an ammonium hydroxide and methanol gradient on a high pH stable SuperC18 column at low temperature was demonstrated to be the most successful chromatographic mode for separating 26 analytes including: regioisomeric fluorofentanyls (n = 10); fentanyl analogues (n = 10), despropionyl precursors (n = 4) and two commonly encountered related substances (heroin and xylazine). Low and intermediate pH RP-UHPLC failed to afford separation of many of the fluorofentanyl regioisomers on stationary phases possessing complementary selectivity with either acetonitrile or methanol over a wide temperature range. HILIC on a bare silica column using an acetonitrile and ammonium acetate / acetic acid gradient provided good separation of fluorofentanyl regiosiomers except for the despropionyl series. High pH gradient RP-UHPLC was demonstrated to provide orthogonal chromatographic selectivity to that of HILIC in the gradient analysis of 18 fentanyl and related substances. Seven isobaric fluorofentanyl structural isomers could be readily discriminated from the unique fragmentation ions obtained using positive electrospray ionization MS/MS. The optimum high pH RP-UHPLC chromatographic conditions for the separation of the fluorofentanyls was equally successful for the rapid separation of a wide range of fentanyl regio- and structural isomers.

本研究描述了低、中、高pH梯度RP-UHPLC-MS/MS与梯度HILIC-MS/MS分析的发展和比较，用于一系列氟芬太尼衍生物，包括四个家族的邻位异构体、间位异构体和准区域异构体。高pH RP-UHPLC-MS/MS使用氢氧化铵和甲醇梯度在高pH稳定的SuperC18柱在低温下被证明是分离26种分析物的最成功的色谱模式，包括：区域异构体氟芬太尼（n = 10）；芬太尼类似物（n = 10），地丙酰前体（n = 4）和两种常见的相关物质（海洛因和噻嗪）。在较宽的温度范围内，低pH和中等pH的RP-UHPLC无法在与乙腈或甲醇具有互补选择性的固定相上分离许多氟芬太尼区域异构体。在裸硅柱上使用乙腈和乙酸铵/乙酸梯度的HILIC可以很好地分离氟芬太尼区域异构体，但地丙基系列除外。高pH梯度RP-UHPLC对18种芬太尼及其相关物质的梯度分析具有较好的正交选择性。利用正电喷雾电离质谱联用技术可以很容易地从分离得到的独特的碎片离子中区分出7种氟芬太尼结构异构体。高pH反相高效液相色谱法分离氟芬太尼的最佳条件同样成功地快速分离了广泛的芬太尼区域和结构异构体。

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引用次数: 0

Exploiting a gold leaf-based voltammetric sensor for the estimation of firing distance 利用金箔伏安传感器估算射击距离

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-21 DOI: 10.1016/j.forc.2025.100681

Thinnapong Wongpakdee , Supatana Buking , Prapin Wilairat , Kanchana Uraisin , Nuanlaor Ratanawimarnwong , Duangjai Nacapricha

In this study, we present a novel electrochemical approach for firing distance estimation using a gold leaf-based sensor integrated with screen-printed electrodes. This is the first report of employing a gold leaf-based sensor for the voltammetric estimation of firing distance by detecting Pb in gunshot residue (GSR) on fabric targets. The sensor consists of a gold leaf sheet as the working electrode, with carbon and silver/silver chloride screen-printed electrodes serving as the counter and reference electrodes, respectively. Pb(II), a key component of GSR, was extracted from 15 mm fabric discs using manual shaking in nitric acid for 3 min. The extracted solution was analyzed by anodic stripping voltammetry (ASV) with a portable electrochemical system. The Pb(II) signal was then correlated with the firing distance to construct an analytical curve for estimation of shooting distance in the range of 5–60 cm. The resulting mathematical model enables accurate distance estimation. This cost-effective, reagent-free, and field-deployable electrochemical sensor offers a rapid and accessible alternative for forensic firearm investigations.

在这项研究中，我们提出了一种新的电化学方法来估计发射距离，该方法使用基于金箔的传感器集成了丝网印刷电极。本文首次报道了利用金箔传感器通过检测织物目标上的枪弹残余物（GSR）中的铅来伏安估计射击距离。该传感器由金箔片作为工作电极，碳和银/氯化银丝网印刷电极分别作为计数电极和参比电极。从15 mm的织物圆盘中提取GSR的关键成分Pb(II)，在硝酸中手动振荡3 min，提取液采用便携式电化学系统阳极溶出伏安法（ASV）进行分析。将Pb（II）信号与发射距离进行关联，构建了估算5 ~ 60 cm范围内发射距离的解析曲线。由此产生的数学模型可以进行精确的距离估计。这种低成本、无试剂、可现场部署的电化学传感器为法医枪支调查提供了一种快速、方便的替代方案。

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引用次数: 0

Discovery of selective markers for chlorine gas exposure in concrete 发现混凝土中氯气暴露的选择性标记物

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-18 DOI: 10.1016/j.forc.2025.100680

Mirjam de Bruin-Hoegée , Bence Dallos , Tomas van Groningen , Jelle de Koning , Latifa Lamriti , Marcel J. van der Schans , Arian C. van Asten

Chlorine gas (Cl₂) is still being used as a chemical weapon in modern war zones. After an attack with this toxic chemical, verifying its use is challenging due to its reactivity and rapid evaporation. Additionally, only a limited number of selective markers relating to the use of chlorine gas are found. For forensic purposes it is necessary to discriminate Cl₂ from other chlorine containing chemicals. Therefore, the current study aims to use gas chromatography–mass spectrometry (GC–MS) and liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS) together with machine learning methods to discover selective markers for chlorine gas exposure. Four types of concrete originating from Europe or the Middle East were exposed to various levels of Cl₂ as well as to some commonly used chlorine containing chemicals. After extraction with various solvents, the samples were analyzed. Based on the tentative identification of 32 chlorinated markers with GC–MS and 146 markers with LC-HRMS/MS, principal component analysis (PCA) and linear discriminant analysis (LDA) models were constructed. A clear distinction between concrete samples exposed to bleach and chlorine gas was apparent. For forensic classification, a Bayesian likelihood ratio (LR) model was applied that showed limited rates of misleading evidence and maximum LRs of 0.038 to 93. The markers chloroacetone, dichloroacetone, tetrachlorophenol, and 5-chloro-8-quinolinol were found to be selective for chlorine gas exposure. Their identity was verified by GC–MS/MS and LC-MS/MS in comparison with commercially available reference standards. In conclusion, this study demonstrates the feasibility of chemical profiling in concrete to differentiate among various chlorinating agents.

氯气（Cl2）在现代战区仍被用作化学武器。在受到这种有毒化学物质的攻击后，由于其反应性和快速蒸发，验证其使用是具有挑战性的。此外，只发现了数量有限的与氯气使用有关的选择性标记。为了法医的目的，有必要将Cl2与其他含氯化学品区分开来。因此，本研究旨在利用气相色谱-质谱（GC-MS）和液相色谱-高分辨率串联质谱（LC-HRMS/MS）结合机器学习方法发现氯气暴露的选择性标记物。来自欧洲或中东的四种混凝土暴露在不同水平的二氧化氯以及一些常用的含氯化学品中。用各种溶剂提取后，对样品进行分析。在对32个氯代标记物进行GC-MS和146个标记物进行LC-HRMS/MS初步鉴定的基础上，建立了主成分分析（PCA）和线性判别分析（LDA）模型。暴露于漂白剂和氯气的混凝土样品之间的明显区别是显而易见的。对于法医分类，贝叶斯似然比（LR）模型显示误导证据率有限，最大似然比为0.038 ~ 93。氯丙酮、二氯丙酮、四氯苯酚和5-氯-8-喹啉酚标记物对氯气暴露具有选择性。用GC-MS /MS和LC-MS/MS与市售标准品进行了鉴别。总之，本研究证明了在混凝土中进行化学分析以区分不同氯化剂的可行性。

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引用次数: 0

Improving inter-laboratory comparability of tooth enamel carbonate stable isotope analysis (δ13C, δ18O) 提高牙釉质碳酸盐稳定同位素分析（δ13C, δ18O）的实验室间可比性

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-14 DOI: 10.1016/j.forc.2025.100679

Chris Stantis , Lesley A. Chesson , Daniel L. Johnson , Thuan H. Chau , Kirsten A. Verostick , Gregory E. Berg , Gabriel J. Bowen

Carbon and oxygen isotope ratios of human tooth enamel carbonate are frequently used for reconstruction of past diet, movement, and environmental conditions. Despite a long legacy of research, samples are prepared and analyzed using a remarkably broad range of protocols, and this methodological heterogeneity raises questions about the comparability of isotopic data across studies. We report a systematic comparison of isotope delta (δ) values for 10 “modern” faunal teeth (obtained from field recoveries) measured in two different laboratories. Our tests included comparisons of enamel powder subsamples that were chemically pretreated using commonly adopted protocols and subsamples that received no pretreatment. We also evaluated δ values generated with and without (1) standardizing the reaction temperature used for sample acidification and (2) baking the samples and vials to remove moisture before analysis. The results showed that δ values from the two laboratories were systematically different when samples were chemically pretreated, but that differences were smaller or negligible for untreated samples. Standardization of acid reaction temperature and baking also improved comparability. We suggest that the widely adopted practice of chemical pretreatment of enamel samples is largely unnecessary and may compromise the accuracy of stable isotope analyses.

Technology Readiness Level: TRL 4.

人类牙釉质碳酸盐的碳氧同位素比值经常用于重建过去的饮食，运动和环境条件。尽管有长期的研究遗产，样品的制备和分析使用了非常广泛的协议，这种方法的异质性提出了关于同位素数据在研究中的可比性的问题。我们报告了在两个不同实验室测量的10个“现代”动物牙齿（从野外恢复获得）的同位素δ值的系统比较。我们的测试包括比较使用常用方案进行化学预处理的搪瓷粉亚样品和未进行预处理的亚样品。我们还评估了在(1)标准化用于样品酸化的反应温度和(2)在分析前烘烤样品和小瓶以去除水分时和在没有(1)标准化用于样品酸化的反应温度下产生的δ值。结果表明，两个实验室的δ值在样品进行化学预处理时存在系统差异，但未处理样品的差异较小或可以忽略不计。酸反应温度和烘烤的标准化也提高了可比性。我们认为，广泛采用的搪瓷样品化学预处理方法在很大程度上是不必要的，可能会损害稳定同位素分析的准确性。技术准备等级：trl4。

{"title":"Improving inter-laboratory comparability of tooth enamel carbonate stable isotope analysis (δ13C, δ18O)","authors":"Chris Stantis , Lesley A. Chesson , Daniel L. Johnson , Thuan H. Chau , Kirsten A. Verostick , Gregory E. Berg , Gabriel J. Bowen","doi":"10.1016/j.forc.2025.100679","DOIUrl":"10.1016/j.forc.2025.100679","url":null,"abstract":"<div><div>Carbon and oxygen isotope ratios of human tooth enamel carbonate are frequently used for reconstruction of past diet, movement, and environmental conditions. Despite a long legacy of research, samples are prepared and analyzed using a remarkably broad range of protocols, and this methodological heterogeneity raises questions about the comparability of isotopic data across studies. We report a systematic comparison of isotope delta (δ) values for 10 “modern” faunal teeth (obtained from field recoveries) measured in two different laboratories. Our tests included comparisons of enamel powder subsamples that were chemically pretreated using commonly adopted protocols and subsamples that received no pretreatment. We also evaluated δ values generated with and without (1) standardizing the reaction temperature used for sample acidification and (2) baking the samples and vials to remove moisture before analysis. The results showed that δ values from the two laboratories were systematically different when samples were chemically pretreated, but that differences were smaller or negligible for untreated samples. Standardization of acid reaction temperature and baking also improved comparability. We suggest that the widely adopted practice of chemical pretreatment of enamel samples is largely unnecessary and may compromise the accuracy of stable isotope analyses.</div><div><strong>Technology Readiness Level</strong>: TRL 4.</div></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"45 ","pages":"Article 100679"},"PeriodicalIF":2.6,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338893","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

Development of a semi-preparative LC method for the purification of synthetic cannabinoids impregnated in herbal products for chemical characterization by NMR and HRMS 建立一种半制备液相色谱法，用于纯化浸渍在草药产品中的合成大麻素，并通过NMR和HRMS进行化学表征

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-10 DOI: 10.1016/j.forc.2025.100678

Karen Rafaela Gonçalves de Araújo , Gabriela de Paula Meirelles , Daniel Pecoraro Demarque , Fabiane Dorr , Luiz Ferreira Neves Júnior , Alexandre Learth Soares , Camila Delanesi Guedes , José Luiz da Costa , Mauricio Yonamine

Synthetic cannabinoids (SCs) now encompass over 360 compounds under international control. Identifying these substances is a significant challenge for law enforcement, as they are new drugs found in herbal fragments, and reference standards are not available for traditional chemical analysis. To address this, substances can be identified using type A analytical techniques, according to the Scientific Working Group for the Analysis of Seized Drugs which are those with the highest level of selectivity and provide structural information, such as nuclear magnetic resonance and mass spectrometry. However, these methods require compound purification for proper characterization. This study aimed to develop a purification method for SCs in herbal fragments to enable chemical analysis. Seized samples were first analyzed using gas chromatography-electron ionization-mass spectrometry (GC-EI-MS). Then, a semi-preparative liquid chromatography (LC) method was applied, successfully isolating SCs and allowing their structural determination through NMR and high-resolution mass spectroscopy. In the first sample, MDMB-CHMINACA was identified as the sole SC. In the second sample, GC-EI-MS analysis revealed a mass spectrum that did not match any library entry. After purification, the substance was identified as ADB-INACA. In the third sample, the method facilitated the separation and structural determination of four SCs (MDMB-INACA, ADB-BUTINACA, MDMB-4en-PINACA, and 5F-ADB) in a mixture from an herbal sample. In conclusion, the method developed for purification using semi-preparative LC for subsequent chemical characterization proved to be effective for the structural determination of new SCs present in herbal drugs seized by the police.

合成大麻素（SCs）目前包括360多种受国际管制的化合物。确定这些物质对执法来说是一项重大挑战，因为它们是在草药碎片中发现的新药，而传统的化学分析没有参考标准。为了解决这个问题，根据分析缉获药物科学工作组的说法，可以使用A类分析技术来识别物质，这些技术具有最高的选择性并提供结构信息，例如核磁共振和质谱。然而，这些方法需要化合物纯化以进行适当的表征。本研究旨在建立一种纯化草药片段中SCs的方法，用于化学分析。首先使用气相色谱-电子电离-质谱（GC-EI-MS）对检获样品进行分析。然后，采用半制备液相色谱（LC）方法，成功分离出SCs，并通过核磁共振和高分辨率质谱对其结构进行测定。在第一个样本中，MDMB-CHMINACA被鉴定为唯一的SC。在第二个样本中，GC-EI-MS分析显示其质谱与任何文库条目都不匹配。纯化后鉴定为ADB-INACA。在第三个样品中，该方法有助于从草药样品混合物中分离和测定四种SCs （MDMB-INACA, ADB-BUTINACA， MDMB-4en-PINACA和5F-ADB）的结构。总之，利用半制备LC进行纯化并进行后续化学表征的方法被证明对警方查获的草药中存在的新SCs的结构测定是有效的。

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引用次数: 0

A multi-modal spectroscopic approach to forensic discrimination of liquid cosmetic complexion products 一种多模态光谱方法用于液体化妆品的法医鉴别

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-06-06 DOI: 10.1016/j.forc.2025.100677

Jesse McEwan , Katy A. Bruce , Kari Pitts , Georgina Sauzier

Foundations and other complexion products such as concealers or beauty balm creams account for a significant proportion of the global cosmetic market. In addition to being widely used across a range of demographics, these products are inherently transferable through contact and have a variety of distinctive formulations, making them potentially valuable as associative evidence. Despite this, the analysis of complexion products for forensic purposes is a relatively under-researched area, with studies to date largely focussed exclusively on foundation products often analysed using a single technique. In this study, 35 liquid complexion products representing 19 international retailers available within Australia were analysed using ATR-FTIR spectroscopy. Initially indistinguishable samples were then analysed using Raman spectroscopy and X-ray diffraction, which have not previously been applied in the open literature for forensic cosmetic analysis, to enhance discrimination. Chemometric pattern recognition based on infrared data resulted in a discrimination accuracy of 98 % between individual products and classification accuracy of 72 % using a blind validation set. Raman spectroscopy and X-ray diffraction each offered enhanced discrimination of similar products primarily based on mineral content, although similar shades of the same product remain challenging. Analysis of eight duplicate samples purchased from the UK retail market revealed no significant compositional differences between batches from global retailers, which has yet to be explicitly investigated in existing studies. This market survey highlights the chemical variability of complexion products that may be exploited for evidential purposes using a multi-modal analytical workflow.

粉底和其他肤色产品，如遮瑕膏或美容乳霜，占全球化妆品市场的很大比例。除了广泛应用于各种人口统计数据之外，这些产品本身具有可通过接触转移的特性，并且具有各种独特的配方，这使得它们作为关联证据具有潜在的价值。尽管如此，用于法医目的的肤色产品分析是一个相对较少的研究领域，迄今为止的研究主要集中在粉底产品上，通常使用单一技术进行分析。在这项研究中，代表澳大利亚19家国际零售商的35种液体肤色产品使用ATR-FTIR光谱进行了分析。最初难以区分的样品，然后使用拉曼光谱和x射线衍射分析，这在以前的公开文献中尚未应用于法医化妆品分析，以增强辨别。基于红外数据的化学计量模式识别在单个产品之间的识别准确率为98%，使用盲验证集的分类准确率为72%。拉曼光谱和x射线衍射都提供了主要基于矿物含量的类似产品的增强辨别，尽管相同产品的相似色调仍然具有挑战性。对从英国零售市场购买的8个重复样品的分析显示，来自全球零售商的批次之间没有显着的成分差异，这尚未在现有研究中明确调查。这项市场调查强调了肤色产品的化学变异性，可以利用多模态分析工作流程用于证据目的。

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引用次数: 0

Analysis of automotive lubricating grease residue: A forensic investigation using ATR-FTIR spectroscopic and chemometric interpretation 汽车润滑油脂残留物的分析：ATR-FTIR光谱和化学计量学解释的法医调查

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-05-29 DOI: 10.1016/j.forc.2025.100670

Dimple Bhatia, Chongtham Nimi, Deepak Kumar, Arti Yadav, Rajinder Singh

Automotive lubricating greases are widely utilized in automobiles, making them frequently encountered trace evidence in incidents involving a vehicle's collision with another vehicle, person, animal, or stationary object. Due to their high transferability, lubricating grease can act as valuable corroborative evidence during crime scene investigations. They can assist in establishing a link between the vehicle and the individual (victim or accused) to the crime scene, while also confirming contact between the vehicle and the victim. In this study, 21 brands of automotive lubricating grease samples were analyzed for their identification and differentiation, employing a rapid and non-destructive ATR-FTIR spectroscopic technique combined with chemometrics. ATR-FTIR spectra of all samples were visually examined and categorized into six groups based on their similarities and differences. After visual examination, the training dataset was subjected to chemometric analysis using PCA and SVM tools. PCA was employed to explore trends within the dataset, while SVM classified samples, achieving 97.62 % training accuracy and 88.09 % external validation accuracy. To ensure an unbiased validation of the SVM model, the training and validation datasets were comprised of a distinct set of spectra. A blind test validated the SVM model, resulting in 100 % prediction accuracy. Additionally, a study was performed to evaluate how substrate type, storage conditions, and storage duration could affect the linking of the substrate grease samples to their source. The findings revealed that the above-mentioned factors, particularly sunlight exposure and the washing of the substrate grease samples, significantly influence the SVM prediction accuracy.

汽车润滑脂在汽车上的应用非常广泛，在车辆与其他车辆、人、动物或静止物体的碰撞事故中，润滑脂经常成为痕迹证据。润滑脂具有很高的可转移性，在犯罪现场调查中可以作为有价值的确证。它们可以帮助建立车辆与犯罪现场的个人（受害者或被告）之间的联系，同时也确认车辆与受害者之间的联系。本研究采用快速、无损的ATR-FTIR光谱技术结合化学计量学，对21个品牌的汽车润滑脂样品进行了鉴定和区分。对所有样品的ATR-FTIR光谱进行目测，并根据相似性和差异性将其分为6组。目视检查后，使用主成分分析和支持向量机工具对训练数据进行化学计量分析。采用PCA对数据集中的趋势进行挖掘，SVM对样本进行分类，训练准确率达到97.62%，外部验证准确率达到88.09%。为了确保支持向量机模型的无偏验证，训练和验证数据集由一组不同的光谱组成。盲测试验证了SVM模型，预测准确率达到100%。此外，还进行了一项研究，以评估基材类型、储存条件和储存时间如何影响基材油脂样品与其来源的连接。结果表明，上述因素，特别是阳光照射和衬底油脂样品的洗涤，显著影响SVM的预测精度。

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引用次数: 0

Correlation of compositional change with visualization enhancement results and morphology evolution of blood based on thermal performance analysis 基于热性能分析的血液成分变化与可视化增强结果及形态演变的相关性研究

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-05-26 DOI: 10.1016/j.forc.2025.100669

Junyi Di , Jing Jin , Zirui Lu , Xinyu Yan , Peibin Wang , Jinzhuan Zhang , Chaoyi Shi

The morphology evolution and compositional change of blood during heating are crucial for understanding the results of visualization enhancement when using chemical reagents. Given the complexity of blood composition, human and two other mammalian blood samples were initially centrifuged and prepared as dried whole blood, dried erythrocytes, and dried plasma for further TG-IR analysis. The results indicated that the decomposition process of blood could be divided into four distinct stages: 35-190 °C, 190-430 °C, 430-610 °C, and 610-800 °C. In the second stage, lipids and proteins underwent thermal decomposition, resulting in an approximately 50 % mass loss of blood with the release of NH₃ and CO₂, and obvious bulges presented with a black metallic appearance due to the rapid release of gases. The bloodstains could be visualized by the luminol test after heating at 310 °C for 5 min. Also, a positive reaction could be obtained by using tetramethylbenzidine (TMB) after heating at 400 °C for 5 min. In the third stage, the mass loss was further reduced by approximately 40 %. The streaks or block-like fractures appeared on the surface, with the metallic luster largely disappearing. Negative visualization results were obtained from bloodstains after heating at 480 °C for 5 min, suggesting that the hemoglobin was completely decomposed. The thermal decomposition process was gradually decreased when heating above 610 °C and completed around 880 °C, with minimal fibrous residues left. The compositional changes of blood during heating were correlated with morphology evolution and visualization enhancement, providing the evidence for blood detection in fire scenes.

在使用化学试剂时，血液在加热过程中的形态演变和成分变化对于理解可视化增强的结果至关重要。考虑到血液成分的复杂性，人类和其他两种哺乳动物的血液样本首先进行离心处理，制备成干燥的全血、干燥的红细胞和干燥的血浆，用于进一步的TG-IR分析。结果表明，血液的分解过程可分为35 ~ 190℃、190 ~ 430℃、430 ~ 610℃和610 ~ 800℃四个阶段。在第二阶段，脂质和蛋白质进行热分解，随着NH3和CO2的释放，血液质量损失约50%，由于气体的快速释放，出现明显的凸起，呈现黑色金属外观。在310°C加热5分钟后，通过鲁米醇测试可以看到血迹。在400°C加热5分钟后，使用四甲基联苯胺（TMB）可以获得正反应。在第三阶段，质量损失进一步降低了约40%。表面出现条状或块状断裂，金属光泽基本消失。在480℃下加热5 min后，血迹可见阴性，说明血红蛋白已完全分解。在610℃以上加热时，热分解过程逐渐减少，在880℃左右完成，纤维残留物最少。加热过程中血液成分的变化与形态进化和可视化增强相关，为火灾现场血液检测提供了依据。

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引用次数: 0

Assessment of adsorption interference from carbonaceous materials in post-explosion residue analysis of fuel–oxidizer mixtures by ion chromatography 离子色谱法评价燃料-氧化剂混合物爆炸后残留物分析中碳质物质的吸附干扰

IF 2.6 3区医学 Q2 CHEMISTRY, ANALYTICAL

Forensic Chemistry

Pub Date : 2025-05-22 DOI: 10.1016/j.forc.2025.100671

Lúcio Paulo Lima Logrado

This study investigated the influence of carbonaceous materials on the extraction and analysis of post-explosion residues by ion chromatography (IC). Three adsorptive materials—activated carbon, carbonized paper residue, and vegetal charcoal—were evaluated for their capacity to retain inorganic ions typically found in combustion/explosion residues of flash powder, black powder, and explosive emulsions. The targeted ions included Cl⁻, NO₂⁻, OCN⁻, ClO₃⁻, NO₃⁻, SO₄²⁻, S₂O₃²⁻, SCN⁻, ClO₄⁻, K⁺, NH₄⁺, and Na⁺. The results showed significant ion-specific retention effects, particularly for oxidizing anions, which varied depending on the type and amount of adsorbent. Additional experiments comparing room temperature and heated (90 °C) aqueous extractions demonstrated that heating does not provide a consistent solution to the problem of ion adsorption. These findings underscore the risk of false negatives or underestimation of analytes caused by the presence of carbon-rich debris, commonly found in post-explosion samples. The study highlights the importance of considering adsorptive interference when selecting sample portions for analysis, prioritizing areas with minimal carbonaceous content. These findings contribute to improving the reliability of IC and other aqueous extraction-based methods used in the forensic analysis of explosive residues.

研究了含碳材料对离子色谱法提取和分析爆炸残留物的影响。对活性炭、炭化纸屑和植物炭这三种吸附材料的吸附能力进行了评估，以确定它们对闪光粉、黑火药和爆炸乳剂燃烧/爆炸残留物中常见的无机离子的吸附能力。目标离子包括Cl−,没有₂−,OCN−,ClO₃−,没有₃−,所以₄2−,S₂O₃2−,SCN−,ClO₄−,K +、NH₄+和Na +。结果显示了显著的离子特异性保留效果，特别是氧化阴离子，这取决于吸附剂的类型和量。另外的实验比较室温和加热（90°C）水萃取表明，加热不能提供离子吸附问题的一致解决方案。这些发现强调了由于爆炸后样品中常见的富含碳的碎片的存在而导致的假阴性或低估分析物的风险。该研究强调了在选择样品部分进行分析时考虑吸附干扰的重要性，优先考虑碳含量最低的区域。这些发现有助于提高IC和其他基于水萃取的方法在爆炸残留物法医分析中的可靠性。

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