Forensic Chemistry最新文献

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

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

Interpretation and report writing in forensic comparisons of paint evidence: An interlaboratory exercise 油漆证据的法医比较的解释和报告写作:一个实验室间的练习

IF 2.7 3区医学

Forensic Chemistry Pub Date : 2023-09-01 DOI: 10.1016/j.forc.2023.100513

Andria Mehltretter , Meghan Prusinowski , Hal Arkes , David Flohr , Cedric Neumann , Scott Ryland , Donna Sirk , Tatiana Trejos

{"title":"Interpretation and report writing in forensic comparisons of paint evidence: An interlaboratory exercise","authors":"Andria Mehltretter , Meghan Prusinowski , Hal Arkes , David Flohr , Cedric Neumann , Scott Ryland , Donna Sirk , Tatiana Trejos","doi":"10.1016/j.forc.2023.100513","DOIUrl":"https://doi.org/10.1016/j.forc.2023.100513","url":null,"abstract":"<div><p>This interlaboratory study evaluated a guide for interpreting and reporting trace evidence examinations. The online survey aimed to assess the examiners' interpretation of casework scenarios designed by a subject matter expert panel (SMEP), specifically for paint evidence. A pool of 30 scenarios was created, and 15 were assigned to each participant using multi-factor design to evaluate agreement among examiners on case sets with different conclusion ranges and difficulty levels. Exploratory data analysis and three generalized mixed-effects models were used to assess the data. From the 1267 responses received from 85 participants, approximately 93% of responses were consistent between participants and within the SMEP consensus and the next best category, while 73% agreed with the SMEP consensus that was considered the ground truth. Most disagreements were observed in worst-case scenarios created with intended higher difficulty and complex circumstances.</p><p>The statistical models showed a strong positive relationship between the reported and expected conclusions, indicating that participants' findings align with the SMEP consensus. On the other hand, the exercise's difficulty level and participant's experience did not have a significant impact on the reported conclusions. However, the credible intervals for the probabilities of the different reported conclusions indicate that more experienced participants achieve greater consensus for a given exercise. The consensus reached among practitioners represents an advance in the trace community’s efforts to standardize reporting of results and opinions when following systematic criteria.</p></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"35 ","pages":"Article 100513"},"PeriodicalIF":2.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1754092","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 and validation of a liquid chromatography tandem mass spectrometry method for the analysis of 53 benzodiazepines in illicit drug samples 液相色谱串联质谱法分析非法药物样品中53种苯二氮卓类药物的建立和验证

IF 2.7 3区医学

Forensic Chemistry Pub Date : 2023-09-01 DOI: 10.1016/j.forc.2023.100512

Heather D. Whitehead , Kathleen L. Hayes , James A. Swartz , Marya Lieberman

{"title":"Development and validation of a liquid chromatography tandem mass spectrometry method for the analysis of 53 benzodiazepines in illicit drug samples","authors":"Heather D. Whitehead , Kathleen L. Hayes , James A. Swartz , Marya Lieberman","doi":"10.1016/j.forc.2023.100512","DOIUrl":"https://doi.org/10.1016/j.forc.2023.100512","url":null,"abstract":"<div><p>An LC-MS/MS method for the analysis of 53 benzodiazepines, including various designer benzodiazepines, was developed. The developed method was applied to a total of 79 illicit street drug samples collected in Chicago, IL. Of these samples, 68 (84%) had detectable amounts of at least one benzodiazepine. Further, of the 53 benzodiazepines included in the developed method just 14 were measured in samples. Clonazolam, a potent designer benzodiazepine and derivative of clonazepam, was the most frequently measured benzodiazepine in 63% of samples and was measured in the highest concentrations. Other benzodiazepines measured in more than 10% of samples included clonazepam, alprazolam, flualprazolam, and oxazepam. Mixtures of benzodiazepines were frequently measured in samples, with just 24% of samples containing just one benzodiazepine. To determine the response of benzodiazepines on a rapid, point-of-use drug checking tool, all 53 benzodiazepine standards were screened on a lateral flow immunoassay benzodiazepine test strip. Sixty eight percent of standards gave a positive BTS response at a concentration of 20 µg/mL, demonstrating BTS have response to a wide variety of benzodiazepines, including many designer benzodiazepines. A comparison of this data to previous data reported for the same samples demonstrated all samples containing a benzodiazepine also had an opioid present, with fentanyl being present in 94% of benzodiazepine samples. These results highlight high rates of polysubstance drug presence in Chicago, IL illicit drug samples, posing an increased risk of drug overdoses in people who use drugs.</p></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"35 ","pages":"Article 100512"},"PeriodicalIF":2.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10358349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1636410","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

Concentration of ignitable liquid residue from simulated fire debris by dynamic vapor microextraction: Sensitivity to instrument settings and debris characteristics 用动态蒸气微萃取法从模拟火灾碎片中提取可燃液体残留物的浓度:对仪器设置和碎片特性的敏感性

IF 2.7 3区医学

Forensic Chemistry Pub Date : 2023-09-01 DOI: 10.1016/j.forc.2023.100511

Jennifer L. Berry , Mary E. Gregg , Amanda A. Koepke , Reta Newman , Kavita M. Jeerage

{"title":"Concentration of ignitable liquid residue from simulated fire debris by dynamic vapor microextraction: Sensitivity to instrument settings and debris characteristics","authors":"Jennifer L. Berry , Mary E. Gregg , Amanda A. Koepke , Reta Newman , Kavita M. Jeerage","doi":"10.1016/j.forc.2023.100511","DOIUrl":"https://doi.org/10.1016/j.forc.2023.100511","url":null,"abstract":"<div><p><span><span>Dynamic vapor microextraction (DVME) is a potential </span>method for the extraction and concentration of ignitable liquid (IL) residue in fire debris. This low flow rate, purge-and-trap headspace concentration method collects IL vapors onto a chilled adsorbent capillary and recovers them by elution with acetone. As an emerging method for fire debris analysis, the sensitivity of DVME performance to instrument settings has yet to be established and, additionally, the effect of variability inherent in authentic fire debris (e.g., water content) has not yet been explored. In this work, we quantitatively evaluate the effect of </span>11 factors via a sensitivity analysis with simulated fire debris. The factors studied included six controllable instrument settings and five reflecting debris characteristics. We quantified performance by covariance mapping between gas chromatography – mass spectrometry (GC–MS) retention time – ion abundance matrices for the recovered eluates and corresponding reference samples. Six factors were found to be significant. IL volume, IL weathering, and debris quantity significantly affected the recovered eluates, whereas water content did not. As related to recovering IL residue from simulated fire debris, recommended instrument settings include a higher oven temperature, longer equilibration time, larger volume of extracted headspace (collection volume), and a lower inlet flow rate. Together with the covariance mapping metric, the fractional factorial design successfully addressed questions about the effect of instrument factors, debris factors, and their interactions with an efficient number of experiments.</p></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"35 ","pages":"Article 100511"},"PeriodicalIF":2.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1754093","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

Monitoring the solid-state VIS profiles of degrading bloodstains 监测降解血迹的固态VIS特征

IF 2.7 3区医学

Forensic Chemistry Pub Date : 2023-09-01 DOI: 10.1016/j.forc.2023.100507

Kgalalelo Rampete , Colin I. Elliott , Theresa Stotesbury

{"title":"Monitoring the solid-state VIS profiles of degrading bloodstains","authors":"Kgalalelo Rampete , Colin I. Elliott , Theresa Stotesbury","doi":"10.1016/j.forc.2023.100507","DOIUrl":"https://doi.org/10.1016/j.forc.2023.100507","url":null,"abstract":"<div><p>Determining the time since deposition (TSD) of bloodstained evidence can be an important process in forensic investigations. Hemoglobin is often examined as a biomolecule of interest for these purposes due to the known <em>ex vivo</em> oxidative changes to its structure. These time-dependent oxidative processes have previously been probed using UV–VIS spectroscopy following the resuspension of bloodstains. Our study investigated the solid-state VIS spectra of degrading bloodstains without sample pre-treatment, effectively bypassing the need for resuspension. A total of 128 bloodstains from eight biological replicates were created and stored on glass slides in four temperature conditions: −20 °C, 4 °C, 22 °C, and 45 °C (see graphical abstract, created with <span>BioRender.com</span><svg><path></path></svg>). Spectra were acquired from 380−800 nm at five time points spanning 96 h. The peak area of the methemoglobin (metHb) band displayed the largest time and temperature differences, an interesting contrast to previous literature using the Soret band for TSD. Principal Component Analysis (PCA) demonstrated that storage temperature delineated the data, with the metHb band showing the greatest contributions to PC1. Linear mixed models from the PCA data with time showed clear TSD relationships with temperature, and with minimal inter-donor variability. Overall, this work complements the UV–VIS analysis of bloodstains for TSD estimation, with the importance of noting clear differences between phases and sample preparation methods.</p></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"35 ","pages":"Article 100507"},"PeriodicalIF":2.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"3448717","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

A novel standard for forensic elemental profiling of polymers by LA-ICP-TOF-MS LA-ICP-TOF-MS法鉴定聚合物元素谱的新标准

IF 2.7 3区医学

Forensic Chemistry Pub Date : 2023-09-01 DOI: 10.1016/j.forc.2023.100515

Mirjam de Bruin-Hoegée , Jorien Schoorl , Peter Zoon , Marcel J. van der Schans , Daan Noort , Arian C. van Asten

{"title":"A novel standard for forensic elemental profiling of polymers by LA-ICP-TOF-MS","authors":"Mirjam de Bruin-Hoegée , Jorien Schoorl , Peter Zoon , Marcel J. van der Schans , Daan Noort , Arian C. van Asten","doi":"10.1016/j.forc.2023.100515","DOIUrl":"https://doi.org/10.1016/j.forc.2023.100515","url":null,"abstract":"<div><p>Plastic materials are often found on crime scenes in improvised explosive devices. Determining the trace-elemental composition of polymer parts may yield discrimination between samples from different sources. Although quantitative laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is well established for forensic glass analysis, the lack of sufficiently reproducible and homogeneous reference standards hampers accurate quantification of trace elements in polymers. Therefore, the present study introduces a new standard for quantitative elemental profiling of polymers. A novel approach was developed for producing polyethylene (PE), polystyrene (PS), and polyvinyl chloride (PVC) standards containing 23 elements at three concentrations. The LA-ICP-TOF-MS measurements showed excellent linear response with R<sup>2</sup> > 0.99 for almost all elements and polymer matrices. Additionally, homogeneity was significantly improved to an average of 10% within-, and 17% between-sample variation. PVC and PE matrices presented the best homogeneity which was confirmed by line ablations. The added value of the standards was demonstrated by evaluating a set of realistic forensic polymer evidence items. The between-run variation was substantially reduced from 42% in absence of calibration to 30% when correcting with an elemental internal standard and even to 24% when applying the novel standards. In addition, its discriminating power between different classes was increased, as demonstrated by ANOVA and principal component analysis. In conclusion, this study shows the feasibility of using a novel standard for quantitative analysis of chemical attribution signatures of trace elements in polymers by LA-ICP-TOF-MS. The use of the polymer standards significantly improves classification and forensic comparison of polymer-based evidence.</p></div>","PeriodicalId":324,"journal":{"name":"Forensic Chemistry","volume":"35 ","pages":"Article 100515"},"PeriodicalIF":2.7,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"1636411","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