The Society of Hair Testing (SoHT) has provided cutoffs for the quantification of ethyl glucuronide (EtG) in hair to indicate occasional or chronic/excessive alcohol consumption. Although several ...sensitive methods have been reported, past proficiency test results show a lack of reproducibility. An ultra-performance liquid chromatographic mass spectrometric method (LLOQ of 10 pg EtG/mg hair) has been validated according to the international guidelines, including the successful participation in five proficiency tests. This method was subsequently used to evaluate the impact of different grinding conditions (cut, weakly or extensively pulverized hair samples) on the final measured EtG concentration. Hair from alcohol consumers (n = 2) and commercially available quality control samples (QCs) (n = 2) was used. For the QCs, extensive pulverization led to a significantly higher amount of measured EtG. In the hair samples obtained from volunteers, cut or weakly pulverized hair resulted in EtG concentrations below the LLOQ, while the mean concentrations of 14 and 40 pg EtG/mg hair were determined after extensive pulverization. Differences in sample preparation could partially explain inter-laboratory variability. As the differences in results can lead to a different interpretation even when applying the SoHT cutoffs, it is of interest to standardize sample preparation techniques in the field of EtG hair testing.
Correction for ‘Changes in latent fingermark glyceride composition as a function of sample age using UPLC-IMS-QToF-MSE’ by Amanda A. Frick, et al., Analyst, 2020, DOI: 10.1039/d0an00379d.
The composition of fingermark residue has been an important topic in forensic science, mainly in efforts to better understand and eventually improve the efficacy of latent fingermark detection ...methods. While the lipid fraction has been extensively studied, there is currently little information about how the glyceride fraction of latent fingermarks is chemically altered over time following deposition. A previously reported untargeted ultra performance liquid chromatography-ion mobility spectrometry-quadrupole time-of-flight mass spectrometry (UPLC-IMS-QToF-MS
E
) method was used to investigate changes over time in fingermark di- and triglycerides. Charged latent fingermark samples from 5 donors were analysed up to 28 days following deposition. Significant changes in glyceride composition occurred with increased sample age, attributed primarily to the oxidation of unsaturated triglycerides through ozonolysis. Considerably fewer unsaturated TGs were identified in samples 7 and 28 days following deposition, while mono- and diozonides of these lipids were identified as major components of aged samples. Additional compounds were identified as possible aldehyde and carboxylic acid derivatives resulting from the reaction of water with ozonolysis intermediates. While the onset of these processes occurred rapidly following deposition, continuing oxidation over time was seen
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the progressive ozonolysis of diunsaturated triglycerides. These results represent a further step towards understanding the factors affecting fingermark composition, ageing and subsequent detection under operational conditions.
An untargeted, lipidomics-based UPLC-IMS-QToF-MS
E
method was used to monitor the formation of triglyceride oxidation products, including ozonides, in latent fingermarks over time.
The composition of fingermark residue has been an important topic in forensic science, mainly in efforts to better understand and eventually improve the efficacy of latent fingermark detection ...methods. While the lipid fraction has been extensively studied, there is currently little information about how the glyceride fraction of latent fingermarks is chemically altered over time following deposition. A previously reported untargeted ultra performance liquid chromatography-ion mobility spectrometry-quadrupole time-of-flight mass spectrometry (UPLC-IMS-QToF-MSE) method was used to investigate changes over time in fingermark di- and triglycerides. Charged latent fingermark samples from 5 donors were analysed up to 28 days following deposition. Significant changes in glyceride composition occurred with increased sample age, attributed primarily to the oxidation of unsaturated triglycerides through ozonolysis. Considerably fewer unsaturated TGs were identified in samples 7 and 28 days following deposition, while mono- and diozonides of these lipids were identified as major components of aged samples. Additional compounds were identified as possible aldehyde and carboxylic acid derivatives resulting from the reaction of water with ozonolysis intermediates. While the onset of these processes occurred rapidly following deposition, continuing oxidation over time was seen via the progressive ozonolysis of diunsaturated triglycerides. These results represent a further step towards understanding the factors affecting fingermark composition, ageing and subsequent detection under operational conditions.
Following a chemical incident involving chemical warfare agents or more broadly, chemical weapons, there are two possible approaches in dealing with the traditional forensic analysis of contaminated ...exhibits. The first is to analyze the contaminated items under safe conditions (i.e. in laboratories dedicated to the handling of such substances), while the second relies on item decontamination prior to processing them in traditional forensic laboratories. One of the main limitations of the latter is the possible degradation or destruction of traces caused by the decontamination process. Hence, it is crucial to have as much information as possible on the impact of different decontamination agents and procedures on traces. This research presents experimental results on the recovery of fingermarks on glass after the application of decontaminants typically used in case of chemical incidents. The impact of 11 decontaminants on fingermarks deposited on glass and on the subsequent enhancement with cyanoacrylate and Small Particle Reagent (SPR) was evaluated (by visual examination) by four evaluators. The results of the study demonstrated that the persistence of fingermarks on glass is highly dependent on the type of decontaminant used. Decontamination agents based on the principle of nucleophilic substitution to neutralize toxic chemicals allowed good subsequent development of fingermarks with SPR. Powdered decontaminants did not show any indication of alteration of fingermarks, whereas decontamination with oxidants leads to variable results.
Correction for 'Changes in latent fingermark glyceride composition as a function of sample age using UPLC-IMS-QToF-MSE' by Amanda A. Frick, et al., Analyst, 2020, DOI: 10.1039/d0an00379d.
The composition of fingermark residue has been an important topic in forensic science, mainly in efforts to better understand and eventually improve the efficacy of latent fingermark detection ...methods. While the lipid fraction has been extensively studied, there is currently little information about how the glyceride fraction of latent fingermarks is chemically altered over time following deposition. A previously reported untargeted ultra performance liquid chromatography-ion mobility spectrometry-quadrupole time-of-flight mass spectrometry (UPLC-IMS-QToF-MS
) method was used to investigate changes over time in fingermark di- and triglycerides. Charged latent fingermark samples from 5 donors were analysed up to 28 days following deposition. Significant changes in glyceride composition occurred with increased sample age, attributed primarily to the oxidation of unsaturated triglycerides through ozonolysis. Considerably fewer unsaturated TGs were identified in samples 7 and 28 days following deposition, while mono- and diozonides of these lipids were identified as major components of aged samples. Additional compounds were identified as possible aldehyde and carboxylic acid derivatives resulting from the reaction of water with ozonolysis intermediates. While the onset of these processes occurred rapidly following deposition, continuing oxidation over time was seen via the progressive ozonolysis of diunsaturated triglycerides. These results represent a further step towards understanding the factors affecting fingermark composition, ageing and subsequent detection under operational conditions.
•Forensic case investigation is taught through problem-based learning activities.•Digital technologies allow for simulating some parts of a forensic case investigation.•Digital tools facilitate this ...teaching to large student cohorts.•Digitised activities promoted students’ critical thinking.•Blended teaching with on-line and on-site activities is more efficient.
Forensic practice is the concluding practical course of the forensic science bachelor program at the School of Criminal Justice of the University of Lausanne. Learning activities are constructed around five main objectives for the resolution of simulated forensic case problems: 1) select relevant traces and items to be collected at the scene and perceive their potential value in the reconstruction process, 2) apply appropriate detection techniques in sequence to obtain clues of good quality, 3) process traces using Analysis, Comparison, Evaluation and Verification (ACE-V) methodology, 4) produce and summarise information in oral and written forms to help an investigation, and 5) work collaboratively to benefit from the diversity of group members. Simulating and supervising realistic activities is a complex task that became more and more challenging with a continuously increasing number of students over the years (from ca. 30 in 2016 to more than 60 in 2021). Thus, an educational innovation project was launched and aimed at implementing digital technologies to support the teaching staff. A computer-based crime scene simulation tool (allowing students to visualize 360° crime scenes and relevant items) and a communication tool (to simplify and centralise the communication between the students and the teaching staff) were implemented. This article describes the implementation, added value and limitations of these digital technologies in problem-based learning activities. Prior to 2020, the practical course forensic practice was delivered entirely on-site without specific technologies, and entirely on-line in 2020 (due to the sanitary restrictions related to the COVID-19 pandemic). Finally, in 2021, on-line and on-site activities were implemented with success, combining the best of both approaches in a blended teaching mode. An overall increase in the satisfaction of students and teaching staff was observed with the implementation of these tools. Limiting presence on-site allowed students to take a step back from the activities and collected items. This promoted critical thinking, and together with an increase in structured (on-line and on-site) interactions allowed for a positive, continuous learning experience. While the evaluations of these novel technologies were very positive, students still expressed their willingness to perform certain tasks on-site and a preference for face-to-face interactions.
•Description and illustration of a field-exercise on CBRN forensic investigation.•Presentation of the operating procedure developed for the investigation.•Discussion on problems encountered and ...solutions proposed.
The GIFT CBRN project (Generic Integrated Forensic Toolbox for chemical, biological, radiological and nuclear incidents), funded under the Seventh Framework Programme of the European Commission, has been set up to find solutions for investigating incidents involving CBRN agents. Regarding the forensic point of view, specific tools and procedures to assist forensic investigators to perform a crime scene investigation (CSI) and methodologies to enable the subsequent analysis of the evidences (contaminated with CBRN agents) seized at the crime scene have been developed. To validate the procedures and methods developed within this project and to test them, three field-exercises engaged with one type of agent at the time (i.e. a RN-agent, a B-agent or a C-agent) has been held. The Belgian Defence Laboratories (DLD) in collaboration with Royal Military Academy (RMA) and the National Institute of Criminalistics and Criminology (NICC) has organized the chemical field exercise in Belgium. CSI teams of the Belgian Federal Police (experienced in crime scene investigation, fingerprints and digital forensics but at the time of the exercise not trained to perform their activities in CBRN conditions), SIBCRA teams (experienced in the sampling and identification of CBRN agents in hazardous environments) and the Civil Protection (experienced in entering zones with potential chemical hazards in full individual protective equipment) were involved. Since those teams never worked together in CBRN conditions, the exercise was used to establish the first operating procedure for CSI and laboratory analysis for CBRN and forensic materials in Belgium. The main steps of the procedure applied during this filed-exercise are described is this manuscript. The first step was the reconnaissance performed to (i) identify/quantify the threat agent involved, (ii) to document the scene and (iii) to collect priority forensic evidences. The second step focused on the collection of other forensic evidences, the sampling of DNA traces and the revelation of fingerprints at the scene. The collection of CBRN agents was performed during step 3. Step 4 concentrated on the decontamination and transport of evidences and traces sampled in the contaminated zone. The revelation of fingerprints in a glovebox (step 5) was finally demonstrated.
In conclusion, this field-exercise was an opportunity for the different Belgium services to work together, to learn from each other, and to work towards the establishment of a national operating procedure to manage investigations in CBRN conditions.
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