Forensic Chemistry Research Articles

Evaluation of interferents in sampling materials for analysis of post-explosion residues (explosive emulsion/ANFO) using gas chromatography-mass spectrometry (GC/MS).

Chemical analysis aimed at identifying post-explosion residues is critical for investigating crimes or accidents involving explosives, establishing it as a vital area of forensic chemistry. In general, only trace amounts remain in samples analyzed for this purpose, making the presence of interferents a constant concern. Therefore, understanding the materials used from collection to sample preparation is essential for this type of analysis. This study focuses on organic contaminants in collection and laboratory materials analyzed by gas chromatography/mass spectrometry (GC/MS), complementing a previous study by Mauricio etal. (2020), which addressed inorganic contaminants in materials used for similar purposes in ion chromatography (IC). No prior studies have specifically investigated the potential organic interferences introduced by various materials commonly used in forensic laboratories for sample pre-processing, storage, and evidence collection in this context. Plastic films, bottle caps, disposable gloves, syringes, swabs, disposable cups, plastic tubes, and plastic pipettes were examined. GC/MS analyses revealed that certain materials, particularly syringe plungers, gloves, and plastic films, can interfere with the detection of post-explosion residues from explosive emulsions and ANFO (ammonium nitrate-fuel oil). These findings emphasize the importance of evaluating materials for potential interferences prior to sample collection and processing to minimize contamination risks. This study provides significant insights into how commonly used laboratory materials can impact forensic analysis, thereby enhancing the reliability of post-explosion residue analysis and supporting more accurate forensic investigations.

A nationwide Swedish retrospective study on poisoning deaths between the years 2000 and 2022.

Approximately 1% of Sweden's 90 000 annual deaths were reported caused by poisoning. In this study, we aim to describe this poisoning population's characteristics, autopsy frequency and results of toxicology testing. A national cohort study based on Swedish national registers. All deceased subjects older than 18 years with poisoning as the cause of death registered between 1 January 2000 and 31 December 2021 were included. Causes of death according to primary ICD-10 code were analysed along with the substances found in forensic chemistry testing. There were 27 057 poisonous deaths during the study periods 2 018 495 adult deaths. Subjects deceased due to poisoning had a median age of 53 years, and 18 838 (70%) were men. A private home was the most reported location of death (52%). In total, 23 260 (87%) did undergo some sort post-mortem examination. Drugs (synthetic narcotics, opioids, heroin) caused 12 448 (46%) deaths, and alcohols explained 9056 cases (33%). Positive toxicological tests were found in 22 550 (83%) of the subjects. The most common separate substances were ethanol, zopiclone and nordazepam. Poisoning caused 1.3% of Swedish deaths. Men in their 50s were the most common victims, and their deaths were often cause by synthetic narcotics, other opioids or alcohol. The autopsy frequency was lower than expected for poisonous deaths.

From forensic chemistry: an educational experience

Abstract The study of forensic chemical analysis not only aids justice in the investigation of accidental or criminal events but also trains chemistry students in analysing hypothetical scenes, such as the design of scientific experiments, and alerting them to potential dangers. In this way, it contributes to generating awareness about safety and security, ethics, and the professional responsibilities of chemists. These, although ambitious, are some of the objectives that have led to the development of this course on Chemical Analysis in Forensic Investigation, whose thematic units and teaching details are developed. This work presents a detailed programme for the Forensic Chemistry course offered at the Faculty of Exact and Natural Sciences at the University of Buenos Aires. It includes examples of activities and bibliography, allowing it to be used as a template for similar courses or to adapt some of the thematic units to other chemistry courses. The suggested bibliography supports the education of both students and educators in the field of forensic chemistry. The incorporation of topics such as fires, explosives, chemical warfare agents (CWA), and environmental crimes aims to develop professional profiles for a new generation of chemists more committed to the societal impact of their work.

Development and Validation of a High-Performance Liquid Chromatography-Ultraviolet Spectrometry Method for Ampicillin and its Application in Routine Therapeutic Drug Monitoring of Intensive Care Patients.

Ampicillin/sulbactam, a combination of a β-lactam and β-lactamase inhibitor, is widely used in clinical settings. However, therapeutic drug monitoring (TDM) of ampicillin is not commonly performed, particularly in intensive care units (ICUs). The purpose of this study was to develop and validate a rapid and cost-effective high-performance liquid chromatography (HPLC)-ultraviolet spectrometry method to quantify ampicillin in human serum and evaluate its clinical application in ICU patients. Sample cleanup included a protein precipitation protocol, followed by chromatographic separation on a C18 reverse-phase HPLC column within 12.5 minutes using gradient elution of the mobile phase. The assay was validated according to the German Society of Toxicology and Forensic Chemistry criteria. Clinical applications involved the retrospective analysis of TDM data from ICU patients receiving continuous infusion of ampicillin/sulbactam, including the attainment of target ranges and individual predicted and observed pharmacokinetics. The method was robust, with linear relations between the peak area responses and drug concentrations in the range of 2-128 mg/L. The coefficient of variation for precision and the bias for accuracy (both interday and intraday) were less than 10%. Clinical application revealed variable pharmacokinetics of ampicillin in ICU patients (clearance of 0.5-31.2 L/h). TDM-guided dose adjustments achieved good therapeutic drug exposure, with 92.9% of the samples being within the optimal (16-32 mg/L) or quasioptimal (8-48 mg/L) range. This method provides a practical solution for the routine TDM of ampicillin, facilitating individualized dosing strategies to ensure adequate therapeutic drug exposure. Given its simplicity, cost-effectiveness, and clinical relevance, HPLC-ultraviolet spectrometry holds promise for broad implementation in hospital pharmacies and clinical laboratories.

Validation of a rapid GC–MS method for forensic seized drug screening applications

With the lack of standardized validation protocols across the forensic chemistry community, validation of instrumentation can be a challenging and time-consuming task. However, this process is crucial to understanding the associated capabilities and limitations, especially for nascent technologies. Rapid GC–MS is one such emerging analytical technique being increasingly implemented in forensic laboratories due to its fast and informative screening capabilities. However, a full validation for forensic samples has yet to be published since its debut. This work presents the results of a comprehensive validation of a rapid GC–MS system for seized drug screening through the assessment of nine components: selectivity, matrix effects, precision, accuracy, range, carryover/contamination, robustness, ruggedness, and stability. Single- and/or multi-compound test solutions of commonly encountered seized drug compounds were used to assess method and system performance. Results met the designated acceptance criteria for a majority of components. For example, retention time and mass spectral search score % RSDs were ≤10 % for precision and robustness studies. Limitations were identified for components that did not meet the acceptance criteria (e.g., inability to differentiate some isomers). The study design is part of a larger validation package developed for rapid GC–MS that includes a validation plan and automated workbook. The template, available for adoption by laboratories, ultimately aims to reduce the barrier of implementation for rapid GC–MS technology.

Designing an Interdisciplinary Forensic Chemistry Lab Module: The Impact of Environmental Factors on Treated Hair with Personal Care Products

Designing an Interdisciplinary Forensic Chemistry Lab Module: The Impact of Environmental Factors on Treated Hair with Personal Care Products

Applications of MALDI mass spectrometry in forensic science.

Forensic chemistry literature has grown exponentially, with many analytical techniques being used to provide valuable information to help solve criminal cases. Among them, matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), particularly MALDI MS imaging (MALDI MSI), has shown much potential in forensic applications. Due to its high specificity, MALDI MSI can analyze a wide variety of compounds in complex samples without extensive sample preparation, providing chemical profiles and spatial distributions of given analyte(s). This review introduces MALDI MS(I) to forensic scientists with a focus on its basic principles and the applications of MALDI MS(I) to the analysis of fingerprints, drugs of abuse, and their metabolites in hair, medicine samples, animal tissues, and inks in documents.

Structural elucidation of tramadol, its derivatives, and metabolites using chemical derivatization and liquid chromatography-high-resolution tandem mass spectrometry.

Tramadol (T) is a strong painkiller drug that belongs to the opioid analgesic group. Several accidental intoxication cases after oral administration of T have been reported in the past decade. Tramadol, its derivatives, and metabolites present information-limited mass spectra with one prominent peak representing the amine-containing residue; therefore, their structural determination based on both electron impact mass spectrometry (EI-MS) and ESI-MS/MS spectra could be misleading. A novel analytical method for the structural elucidation of tramadol, its four homologs, and its two main phase I metabolites (N-desmethyltramadol and O-desmethyltramadol) was developed using chemical modification and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS) with Orbitrap technology. After chemical derivatization, each of the investigated T series exhibited informative mass spectra that enabled better exposition of their structures. The developed method was successfully implemented to explicitly identify the structures of tramadol and its N-desmethyltramadol metabolite in urine samples at low ng/mL levels. An efficient derivatization-aided strategy was developed for rapidly elucidating the structure of tramadol-like compounds. The method is intended to assist forensic chemists in better diagnosing T and its analogs and metabolites in clinical or forensic toxicology laboratories.

Interlaboratory comparison of phosphatidylethanol in dried blood spots using different sampling devices.

Phosphatidylethanol (PEth) has become an important marker to assess drinking behaviour and monitor abstinence. Despite its increasing use, knowledge on robustness and standardization and comparability of methods and results are still limited. In 2022, the first international consensus for the use of PEth and its interpretation was published. To establish an experience-based foundation for further harmonization, three rounds of interlaboratory comparison using microsamples were conducted. Participating laboratories sent their sampling devices to the laboratory of Forensic Toxicology at the University of Bern, where for each round, four different authentic blood samples were applied to the devices and sent back. The PEth 16:0/18:1 target concentrations covered a range between 16 and 474 ng/mL (0.023 and 0.676 μmol/L, respectively) and included sample concentrations close to the decision limits of 20 and 200 ng/mL (0.025 and 0.28 μmol/L, respectively). Evaluation of the results based on guidelines by Horwitz and the Society of Toxicological and Forensic Chemistry (GTFCh) showed that 73% of all participating laboratories quantified and reported all samples (N = 4 for each round) within the acceptable limits. More than 90% quantified and reported at least one sample within the acceptable limits.

Formulation of propositions for forensic handwriting examinations

AbstractThe forensic examiner's role is to assist the court by explaining the significance of their findings within the context of the case. In “evaluative” reporting this is achieved by considering the probability of observing the evidence given at least two competing propositions. This article outlines the requirements of propositions within an evaluative framework, common sets of propositions used in handwriting examinations and their associated basic expectations. As the forensic handwriting examiner may be asked to undertake different types of comparisons depending on the material available and the case circumstances, it is critical that examiners carefully consider the most appropriate propositions against which the findings are to be evaluated. Further, as the propositions are derived from case information, and may require assumptions to be drawn, the necessary disclosure within reports is discussed. Although the examples given are specific to handwriting examinations, the concepts discussed in this article are applicable to other forensic disciplines utilizing an evaluative approach to evidence interpretation.This article is categorized under: Forensic Chemistry and Trace Evidence > Presentation and Evaluation of Forensic Science Output Jurisprudence and Regulatory Oversight > Expert Evidence and Narrative

Forensic chemistry in a pedagogical workshop: mobilizing teaching and learning for high school students

Forensic chemistry in a pedagogical workshop: mobilizing teaching and learning for high school students

Forensic intelligence: Expanding the potential of forensic document examination

AbstractForensic document examination is characterized by its longevity, diversity, and evolution over time. Predominantly, published research within this field has focused on handwriting examination, the articulation of forensic conclusions, and the development of technical instrumental advancements, focusing on the use of document examination in the resolution of casework. This is a persistent and common problem within forensic science that Kirk identified in 1963 and that other authors have reaffirmed more recently. Ultimately, this has resulted in the potential of forensic intelligence, remaining relatively underexplored in the field of document examination. Forensic intelligence is a different way to view and analyze traces, shifting the focus from the traditional identification of source and activity, to instead identifying trends in criminal activity to assist in the reduction, prevention, and proactive disruption of crime. Despite a distinct disparity between these strands of research, there has been a persevering evolution toward the implementation of a systematic forensic intelligence method for the examination of fraudulent identity documents. Since its initial inception into the research community, this method has expanded and been implemented across Europe, and Canada, with tests also being conducted in Australia. These first tangible steps toward a forensic intelligence capacity within document examination have also inspired new work using forensic intelligence and systematic comparisons within the field of handwriting examination, as well as the recognition of the transversal potential of this method, with it being applied to both physical and digital documents. In this review, the fields of document examination and forensic intelligence will first be introduced, along with a subsequent examination of the research that has led to the creation of a forensic intelligence model within the field of document examination. It should be noted that this review has largely been limited to a review of research that has been published in English and French due to the language of the authors.This article is categorized under: Crime Scene Investigation > From Traces to Intelligence and Evidence Forensic Chemistry and Trace Evidence > Emerging Technologies and Methods Crime Scene Investigation > Epistemology and Method

Unlocking Mysteries: A Multidisciplinary Approach to Forensic Science

Abstract: “Unlocking Mysteries: A Multidisciplinary Approach to Forensic Science” delves into the collaborative landscape of forensic investigations, where biology, chemistry, physics, psychology, and law converge to shed light on criminal mysteries. By exploring foundational principles, techniques, and challenges, the chapter emphasizes the importance of multidisciplinary collaboration in deciphering clues left at crime scenes. It outlines seven foundational principles guiding forensic investigations, from the Law of Individuality to the Principle of Analysis. The chapter discusses various forensic analysis techniques, including DNA analysis, fingerprint analysis, toxicology analysis, ballistics analysis, forensic anthropology, forensic chemistry, digital forensics, and trace evidence analysis. DNA analysis, as a cornerstone, aids in individual identification and resolving disputes. Forensic entomology and anthropology provide insights into post-mortem intervals and victim identification. Chemistry techniques like spectroscopy and chromatography aid in identifying substances. Trace evidence analysis offers valuable insights into crime circumstances. The integration of biology into forensic science enhances accuracy and provides closure to victims’ families. The chapter concludes by emphasizing the indispensable role of multidisciplinary collaboration, innovative technologies, and ethical standards in pursuing truth and justice in forensic science. Keywords: forensic science, multidisciplinary collaboration, forensic analysis techniques, DNA analysis, forensic entomology, forensic anthropology, chemistry techniques, trace evidence analysis

Francesco De Bon.

"I would have liked to have discovered one of the 10 artificial elements discovered by Glenn Theodore Seaborg and collaborators, such as plutonium or americium… My secret/not-so-secret passion is watching police procedural dramas. I've watched so many that I am seriously considering enrolling, sooner or later, in the MSc program in Forensic Chemistry at the University of Coimbra…" Find out more about Francesco De Bon in his Introducing… Profile.

A journey into the innovations and expertise of Dubai police and the general department of forensic science and criminology

This manuscript offers an in-depth exploration of the Dubai Police and its General Department of Forensic Science and Criminology, emphasizing their critical role in law enforcement through advanced forensic science and innovative practices. Beginning with a historical overview, it traces the evolution of forensic disciplines from Edmond Locard's foundational principles to Sir Alec Jeffreys' groundbreaking DNA profiling techniques. The manuscript details the structure and functions of specialized sections within the department, including Biology and DNA, Forensic Chemistry, Forensic Toxicology, Firearms and Tool Marks, Questioned Documents, Forensic Explosive, Forensic Fire Investigation, Forensic and Mechanical Engineering, and Nuclear Physics. Key achievements, such as the Biology and DNA Section's processing of thousands of cases and the generation of highly discriminating DNA profiles, are highlighted. The manuscript also addresses the department's challenges, including the rapid evolution of technology and the increasing complexity of crimes. Future plans to enhance capabilities through investment in new technologies, international collaboration, and continuous professional development are outlined. By showcasing the department's commitment to innovation, excellence, and public safety, this manuscript underscores the pivotal contributions of the Dubai Police and its forensic department to crime resolution and community safety. The insights provided aim to foster a deeper understanding of the critical role of forensic science in the criminal justice system.

Raman Spectroscopy for the Time since Deposition Estimation of a Menstrual Bloodstain.

Forensic chemistry plays a crucial role in aiding law enforcement investigations by applying analytical techniques for the analysis of evidence. While bloodstains are frequently encountered at crime scenes, distinguishing between peripheral and menstrual bloodstains presents a challenge. This is due to their similar appearance post-drying. Raman spectroscopy has emerged as a promising technique capable of discriminating between the two types of bloodstains, offering invaluable probative information. Moreover, estimating the time since deposition (TSD) of bloodstains aids in crime scene reconstruction and prioritizing what evidence to collect. Despite extensive research focusing on TSD estimations, primarily in peripheral bloodstains, a crucial gap exists in determining the TSD of menstrual bloodstains. This study demonstrates how Raman spectroscopy effectively analyzes biological samples like menstrual blood, showing similar aging patterns to those of peripheral blood and provides proof-of-concept models for determining the TSD of menstrual blood. While this work shows promising results for creating a universal model for bloodstain age determination, further testing with more donors needs to be conducted before the implementation of this method into forensic practice.

Long-term storage for reanalysis purposes: A stability study of extracts from post-explosion/burning residues of fuel-oxidizer explosive mixtures

Post-explosion residue analysis is vital in forensic chemistry, providing valuable insights into incidents involving explosives. One significant challenge in this field is preserving samples for long-term storage for reanalysis. Presently, many laboratories conducting post-explosion analyses worldwide do not retain samples for reanalysis purposes, since the extraction process for sample preparation often necessitates the complete consumption of the scarce material. Even in cases where a portion of the material remains, such as a swab, it is difficult to ensure its representativeness and select a specific portion for preservation. One possible solution to overcome this challenge is to consider preserving the extracts used in the analyses for potential reanalysis. However, the stability characteristics of these extracts are currently unknown. The results presented in this article provide valuable insights into the feasibility of long-term storage for samples containing target analytes in extracts from post-explosion/burning residues of frequently encountered fuel-oxidizer explosive mixtures, such as flash powder, explosive emulsion, and black powder. These results shed light on the potential viability of preserving such extracts for future reanalysis, offering promising prospects for enhancing forensic investigations in this field. Based on the current findings, it has been demonstrated that the aqueous extracts can be effectively preserved as long-term storage samples for a minimum of 24 months, encompassing all the studied explosives. Only cyanate ion showed significant degradation among the 27 compounds studied. Additionally, the organic extract, specifically in the case of emulsion explosive, can be maintained for at least 12 months.

Using forensic intelligence as a model for determining future toxicology methods: TBI forensic toxicology and forensic drug chemistry nitazene identification.

The Tennessee Bureau of Investigation (TBI) serves all 95 counties of Tennessee, but the data included in this article are primarily focused in Upper East and East Tennessee (the parts of the state included in the eastern time zone). The forensic chemistry (seized drug) unit of the TBI began reporting nitazene analogues in late 2019. The primary analogues found in forensic chemistry cases were isotonitazene and metonitazene. After discussion and review of reporting statistics, the forensic toxicology unit began to monitor for these compounds in toxicology samples by using ion characteristics with the nitazene analogues. Between March 2021 and December 2023, TBI toxicology received 49,639 cases statewide. Of those, 20,105 (40.5%) received toxicology testing. Approximately 95% of TBI toxicology cases are related to Driving Under the Influence (DUI)/motor vehicle-related incidents. Fatal overdoses and cases from the medical examiner office comprise <5% of TBI toxicology caseload. The toxicology section utilizes the SCIEX 3200 Qtrap with a SCIEX Exion LC AC autosampler system to monitor multiple reaction monitoring transition of nitazene analogues. The ion monitoring for two nitazene analogues, isotonitazene and metonitazene, started in March 2021. Ion monitoring should not be construed as a confirmed result but rather as an indication that a drug may be present. A comparison of this data from the forensic toxicology and forensic chemistry units revealed the rise of new drugs that required a more in-depth review to understand the magnitude and scope. This article is also intended to encourage collaboration between forensic toxicology and forensic chemistry (seized drug) units.

Mass spectrometry based proteomics: Changing the impact of protein analysis in forensic science

AbstractMass spectrometry‐based proteomics, born from the invention of soft ionization, has revolutionized protein analysis. In‐depth characterization of complex and variable mixtures of proteins, such as that found at crime‐scenes, is now possible. This capability continues to expand with advancements in mass spectral instrumentation and computational power, allowing for the development of dynamic data acquisition approaches and sophisticated bioinformatics tools for data interpretation. Proteins are the major component of all biological material, as a result they have been of interest to forensic practitioners for centuries. While DNA is the gold standard for identification, proteins are able to provide contextual information about biological material not available through genomic approaches alone. Mass spectrometry‐based proteomics has expanded the breadth and ease of forensic protein analysis with several emerging applications that promise to become common place as investigative tools, particularly in forensic serology and toxicology. This includes the targeted analysis of protein biomarkers for the classification of biological tissue and fluids, the detection of protein toxins such as ricin and identification of peptide hormones such as insulin. The ability of protein analysis to leverage information from the genome has been demonstrated to achieve individual identification from biological material, an emerging technology that can be used in the absence of extractable DNA. In recent years, there has been considerable scrutiny of forensic techniques that lack objectivity and a statistical basis, an alternative molecular approach for forensic analysis that utilizes the high specificity of mass spectrometry, is a welcome addition with many potential future applications.This article is categorized under: Forensic Chemistry and Trace Evidence &gt; Trace Evidence

Isolation and characterization of reference standard candidates for cocaine and benzoylecgonine obtained from illicit substances seized.

The area of forensic chemistry has been growing and developing as a line of research due to the high demands of public safety that require increasingly reliable results due to their importance in criminalistics. In this way, the development of new technologies that help this area, whether in the identification and quantification of drugs or the fight against fraud, becomes promising. In this context, the present work explored the production of reference standards from the purification of cocaine/crack samples seized by the Civil Police of the State of Espírito Santo. Cocaine was purified using chromatographic techniques, and benzoylecgonine was synthesized from purified cocaine. All substances were characterized by ultra-high-resolution mass spectrometry and nuclear magnetic resonance. Homogeneity and stability studies were also performed with benzoylecgonine, and the results were evaluated using analysis of variance (ANOVA). Cocaine and benzoylecgonine showed purities of 98.37% and 96.34%, respectively. The homogeneity of the batch, short-term stability, and other parameters were also evaluated, which together indicate this proposal as promising in the development of reference standards for drugs of abuse from samples seized by the Brazilian forensic police.