Organic and inorganic gunshot residues on the hands, forearms, face, and nostrils of shooters 30 min after a discharge.

During the investigation of firearm-related incidents, gunshot residues (GSR) can be collected on the scene and individuals (e.g., shooters or bystanders).

Breaking barriers in passive sampling: The potential of PTFE membranes in the monitoring of hydrophilic micropollutants.

Passive samplers are key tools to sample hydrophilic micropollutants in water. Two main approaches address the influence of hydrodynamics: (1) determining site-specific sampling rate (R) by characterizing k, the mass transfer coefficient of the water-boundary layer (WBL), and (2) reducing WBL impact using a diffusive material to control the uptake. The first requires calibration data and the second has only been achieved using fragile diffusive material.

Signs of how the Sydney Declaration article is received in the forensic science literature.

The Sydney Declaration is an initiative led by an informal group of forensic scientists with diverse backgrounds. It offers a vision of forensic science based on the trace, as a vestige of a past event related to security or a possible law violation. An article published in Forensic Science International (FSI) introduces to this view [1].

A common framework to situate digital and physical traces in time.

In this article, three main approaches to situate forensic traces in time were revisited under the prism of the Sydney Declaration and adapted to be applicable to a large range of physical and digital traces. The first approach is based on time tags which are time-based characteristics produced as the result of an activity at a specific time. They can either be directly related to time (i.

Technical note: Influence of the drying position and time on the persistence of gunshot residues on fabrics.

The influence of the drying position and time on the persistence of gunshot residues (GSR) on fabrics was investigated. Powder tattooing from a 40 cm shooting distance on targeted fabrics were slightly wetted using a spray and dried for 3 h or 48 h in horizontal or vertical positions. The GSR particles were visualised using IR fluorescence with a Video Spectral Comparator (VSC) and automatically counted with a software before the wetting and after the drying stages.

A comparison of the natural and groomed fingermark lipid composition of different donors using GC/MS.

The lipid composition of natural fingermarks was studied and compared with the composition of groomed residue. Approximately 100 specimens were collected from 6 donors over three sessions (in October, December and July) and analysed using gas chromatography / mass spectrometry (GC/MS). The measured lipid content was generally lower and more variable in natural fingermarks than in groomed fingermarks.

Should inorganic or organic gunshot residues be analysed first?

Gunshot residues (GSR) collected during the investigation of firearm-related incidents can provide useful information for the reconstruction of the events. Two main types of GSR traces can be targeted by forensic scientists, the inorganic (IGSR) and the organic GSR (OGSR). Up to now, forensic laboratories have mainly focused on the detection of inorganic particles on the hands and clothes of a person of interest using carbon stubs analysed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM/EDS).

Towards more relevance in forensic science research and development.

Many different issues have been identified in forensic science for more than 10 years. While quality management has often been suggested as a path forward, research is generally considered as an essential part of the solution. Through an overview of current forensic science research, this paper aims at evaluating if and how research answer the challenges forensic science is currently facing.

An improved Chemcatcher-based method for the integrative passive sampling of 44 hydrophilic micropollutants in surface water - Part A: Calibration under four controlled hydrodynamic conditions.

When monitoring water quality with hydrophilic integrative passive sampling devices, it is crucial to use accurate sampling rates (R) that account for exposure conditions such as hydrodynamics. This study aims at calibrating Chemcatcher-like passive samplers - styrene-divinylbenzene reverse phase sulfonate (SDB-RPS) extraction disk covered by a polyethersulfone (PES) membrane - at four water flow velocities (5 to 40 cm s) in a channel system. First, the four hydrodynamic conditions were characterized by measuring the mass transfer coefficients of the water boundary layer (k) at the surface of the samplers using the alabaster dissolution method.

An improved Chemcatcher-based method for the integrative passive sampling of 44 hydrophilic micropollutants in surface water - Part B: Field implementation and comparison with automated active sampling.

Integrative passive sampling is particularly useful in the monitoring of hydrophilic contaminants in surface water, but the impact of hydrodynamics on contaminant uptake still needs to be better considered. In part A (Glanzmann et al., 2023), Chemcatcher-like hydrophilic samplers (i.

The potential of digital technologies in problem-based forensic learning activities.

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.

An efficient method to detect series of fraudulent identity documents based on digitised forensic data.

Document fraud is a transnational form of crime, and its serial character has already been highlighted. To combat this phenomenon, the Interstate Database of Fraudulent Identity Documents (BIDIF) has been created and implemented in Switzerland. It supports the comparison of documents and the detection of series, i.

Comparison of four commercial solid-phase micro-extraction (SPME) fibres for the headspace characterisation and profiling of gunshot exhausts in spent cartridge casings.

Headspace solid-phase micro-extraction (SPME) is a promising technique for the characterisation and profiling of gunshot exhausts in spent cartridge casings, especially for health and environmental risk assessments, as well as forensic purposes. To date, however, no comprehensive investigation has been carried out to objectively assess the kinds of compound released during a discharge that can be recovered by this approach, the selectivity of the main commercially available fibres, and their relative performances for the analysis of gunshot exhausts and the discrimination of different ammunition types. This study aimed to fill this gap.

Determining the Mass Transfer Coefficient of the Water Boundary Layer at the Surface of Aquatic Integrative Passive Samplers.

Passive sampling devices (PSDs) offer key benefits for monitoring chemical water quality, but the uptake process of PSDs for hydrophilic compounds still needs to be better understood. Determining mass transfer coefficients of the water boundary layer () during calibration experiments and in situ monitoring would contribute toward achieving this; it allows for combining calibration data obtained at different temperature and hydrodynamic conditions and facilitate the translation of laboratory-derived calibration data to field exposure. This study compared two measurement methods applied to extraction disk housings (Chemcatcher), namely, alabaster dissolution and dissipation of performance reference compounds (PRCs) from silicone.

An application example of the likelihood ratio approach to the evaluation of organic gunshot residues using a fictional scenario and recently published data.

The analysis of gunshot residues (GSR) can provide important information with regard to the involvement of a person of interest (POI) in a firearm-related incident. Organic gunshot residues (OGSR) have been investigated in order to provide additional and complementary information to the traditional inorganic gunshot residue (IGSR) particles detected by scanning electron microscopy (SEM). Currently, many procedures and analytical methods have been developed to detect OGSR-related compounds collected from the shooter's hands.

Shifting forensic science focus from means to purpose: A path forward for the discipline?

Forensic science is facing a persistent crisis that is often addressed by organizational responses, with a strong focus on the improvement and standardisation of means and processes. However, organisations and processes are highly dependent on the political, economical and legal structures in which they operate. This may explain why most proposed solutions had difficulties in addressing the crisis up to now, as they could hardly be applied transversally to all forensic science models.

A different perspective on the forensic science crisis.

Recurrent mentions of a forensic science crisis are reported in the literature. Some 15 years ago, the discussion was focused on the backlog problem. Other issues have been regularly debated since then, including the risk of error, need for independence, importance and risk of contextualisation, increasing fragmentation into separate processes and specialisations.

Use of ion mobility-high resolution mass spectrometry in metabolomics studies to provide near MS/MS quality data in a single injection.

The use of ion mobility separations (IMSs) in metabolomics approaches has started to be deeply explored in the last years. In this work, the use of liquid chromatography (LC) coupled to IMS-quadrupole time-of-flight mass spectrometry (QTOF MS) has been evaluated in a metabolomics experiments using single injection of the samples. IMS has allowed obtaining cleaner fragmentation spectra, of nearly tandem MS quality, in data-independent acquisition mode.

Can forensic science learn from the COVID-19 crisis?

This paper draws parallels between the current COVID-19 crisis and the apparent forensic science crisis. It investigates if shared approaches of the problem and solutions could emerge. Some relevant aspects of the medical system as it reacted to the pandemic crisis and the situation in forensic science are presented.

Correction: Changes in latent fingermark glyceride composition as a function of sample age using UPLC-IMS-QToF-MS.

Correction for 'Changes in latent fingermark glyceride composition as a function of sample age using UPLC-IMS-QToF-MS' by Amanda A. Frick, et al., Analyst, 2020, DOI: .

Changes in latent fingermark glyceride composition as a function of sample age using UPLC-IMS-QToF-MS.

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.

The potential of collaborative learning as a tool for forensic students: Application to signature examination.

Transferring theoretical knowledge to practical skills remains a big challenge in forensic science, especially in questioned documents. The examination of handwriting and signatures requires years of practice to develop the necessary skills. While students (and to some extent the general population) often have the impression that it is easy to differentiate handwriting from different persons, in practice, particularly when dealing with simulated signatures, there is a high risk of reaching a wrong conclusion when questioned document experts do not use a systematic approach and/or are not sufficiently experienced (see for example the famous French Dreyfus case).

Time since last discharge of firearms and spent ammunition elements: state of the art and perspectives.

The estimation of the time since last discharge of firearms or spent ammunition elements (e.g., casings) may provide crucial information in the investigation of a shooting incident and, eventually, the following trial.