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Condom residues may be encountered in forensic investigations as traces in sexual assault or rape cases. Casework studies have shown the value of distinguishing condom residues from other types of personal products used by women. However, up to now, there has been no investigation of their chemical variability within an international context. This work employed attenuated total reflectance Fourier transform infrared spectroscopy with chemometrics to provide objective characterisation of condom lubricants and personal hygiene products from the international market. 166 samples were obtained covering five major classes of products likely to be used by women. Principal component analysis distinguished most major classes based on their spectral profiles, with subsequent support vector machine models yielding discrimination accuracies over 90%. A two-step approach was subsequently developed and enabled both classification and a discrimination accuracy of 100%. This could provide greater confidence in chemical discrimination of residues from these products when conducting investigations and help assess the origin of the chemical profile obtained. Further testing using three validation sets produced an identification accuracy of 100% for generic classes, which may allow investigative leads to be more readily obtained from recovered evidence.

Metal homeostasis is integral to normal plant growth and development. During plant–pathogen interactions, the host and pathogen compete for the same nutrients, potentially impacting nutritional homeostasis. Our knowledge of outcome of the interaction in terms of metal homeostasis is still limited. Here, we employed the X-ray fluorescence microscopy (XFM) beamline at the Australian Synchrotron to visualize and analyse the fate of nutrients in wheat leaves infected with Pyrenophora tritici-repentis, a necrotrophic fungal pathogen. We sought to (i) evaluate the utility of XFM for sub-micron mapping of essential mineral nutrients and (ii) examine the spatiotemporal impact of a pathogen on nutrient distribution in leaves. XFM maps of K, Ca, Fe, Cu, Mn, and Zn revealed substantial hyperaccumulation within, and depletion around, the infected region relative to uninfected control samples. Fungal mycelia were visualized as thread-like structures in the Cu and Zn maps. The hyperaccumulation of Mn in the lesion and localized depletion in asymptomatic tissue surrounding the lesion was unexpected. Similarly, Ca accumulated at the periphery of the symptomatic region and as microaccumulations aligning with fungal mycelia. Collectively, our results highlight that XFM imaging provides the capability for high-resolution mapping of elements to probe nutrient distribution in hydrated diseased leaves in situ., Synchrotron X-ray fluorescence microscopy elemental maps highlight major nutrient re-distribution during disease progression.

Forensic investigations are often reliant on physical evidence to reconstruct events surrounding a crime. However, there remains a need for more objective approaches to evidential interpretation, along with rigorously validated procedures for handling, storage and analysis. Chemometrics has been recognised as a powerful tool within forensic science for interpretation and optimisation of analytical procedures. However, careful consideration must be given to factors such as sampling, validation and underpinning study design. This tutorial review aims to provide an accessible overview of chemometric methods within the context of forensic science. The review begins with an overview of selected chemometric techniques, followed by a broad review of studies demonstrating the utility of chemometrics across various forensic disciplines. The tutorial review ends with the discussion of the challenges and emerging trends in this rapidly growing field.

HFE-7100 is a routine carrier solvent in amino acid-sensitive fingermark detection reagents such as ninhydrin and 1,2-indanedione/zinc chloride (IND/Zn). However, a potential EU ban on hydrofluoroethers may require reformulation of these treatments worldwide. Solstice® PF has shown promise as a replacement for HFE-7100 in the United Kingdom. However, the performance (and hence optimal formulation) of IND/Zn is impacted by differences in climate and substrate composition, necessitating assessments under local conditions for different regions. We present a series of preliminary investigations in an Australian context, using the IND/Zn formulation used by Australian forensic service providers. The general performance of Solstice® PF-based IND/Zn was comparable to that using HFE-7100 on three substrate types, three ageing periods (1, 7 and 30 days) and 5 donors. However, slight differences in colour and luminescence intensity, as well as increased ink diffusion, suggest chemical interactions with other reagent components that may affect stability. Specifically, Solstice® PF-based reagent formed a precipitate within a month of storage, though this did not affect performance over a 4 month period. HFE-7100-based IND/Zn was found to be marginally more effective than Solstice® PF when applied to incidental fingermarks. These results indicate that Solstice® PF is a satisfactory alternative carrier solvent to HFE-7100 in an Australian context, though users should be aware of possible limitations regarding compatibility with other evidence components (particularly inks) and shelf-life.

This study compared the composition and effectiveness of three active 1,2-indanedione-zinc (IND-Zn) formulations for the detection of latent fingermarks on a variety of substrates commonly encountered in Seychelles. Fingermarks on five porous substrates were treated using IND-Zn formulations operationally used by the Australian Federal Police (AFP), UK Centre for Applied Science and Technology (CAST), and German Bundeskriminalamt (BKA). Despite the variations in composition, primarily associated with the difference in the carrier solvents, all three formulations gave similar sensitivity. However, BKA was identified as the most effective formulation in consideration of cost and supply chain issues, which could be adopted for use in resource-limited micro-jurisdictions with minimum modification. Further experiments also found that using ethanol as a substitute co- solvent to methanol did not significantly reduce sensitivity, which could provide a safer modification of the CAST formulation used in other regions. The findings provide the basis for developing an effective but sustainable IND-Zn formulation for the Seychelles Police, resilient to the challenges of resource limitations and supply chain disruption, which may also be applicable to other micro-jurisdictions.

Analysis of the epicuticular wax layer on the surface of plant leaves can provide a unique window into plant physiology and responses to environmental stimuli. Well‐established analytical methodologies can quantify epicuticular wax composition, yet few methods are capable of imaging wax distribution in situ or in vivo. Here, the first report of Fourier transform infrared (FTIR) reflectance spectroscopic imaging as a non‐destructive, in situ, method to investigate variation in epicuticular wax distribution at 25 µm spatial resolution is presented. The authors demonstrate in vivo imaging of alterations in epicuticular waxes during leaf development and in situ imaging during plant disease or exposure to environmental stressors. It is envisaged that this new analytical capability will enable in vivo studies of plants to provide insights into how the physiology of plants and crops respond to environmental stresses such as disease, soil contamination, drought, soil acidity, and climate change., Fourier transform infrared (FTIR) reflectance spectroscopic imaging has been used to image epicuticular waxes on the surface of plant leaves, in living plants, to observe how plant physiology changes in response to environmental stressors or disease.

Forensic science has become an indispensable tool for even the smallest of jurisdictions. However, micro-jurisdictions often face significant challenges with respect to resource availability, administration and local governance. This paper examines the forensic service provision in Seychelles as an example of a micro-jurisdiction forensic delivery system. The impact of limited resources and remote access to consumables or services have prompted the prospective shift to localise commonly utilised forensic services. The potential for a solid foundation for a sustainable forensic service is examined in relation to jurisdictions with more advanced forensic service delivery. Reforms of the legal framework, administration, and governance structures are some of the key underpinnings for an effective forensic delivery system built on a culture of transparent science that promotes justice and creates public confidence., Graphical abstract Image 1, Highlights • The Seychelles as an example of a micro-jurisdiction forensic delivery system. • Geographically remote location brings challenges to sustainable service provision. • Current investment into capacity building of commonly utilised forensic services. • Innovative solutions required for effective and efficient forensic delivery system. • Transparent science culture needed to promote justice and create public confidence.

This study explores trends in the effectiveness of 1,2-indandione/zinc chloride (IND/Zn) for visualizing latent fingermarks on paper substrates of various ages. Preliminary investigation of contemporaneous documents showed that high quality fingermarks could be deposited through incidental handling, although smudging and overlapping were evident. IND/Zn was then applied to incidentally handled documents up to 80 years old and successfully developed potentially identifiable fingermarks, significantly increasing the established timescale for fingermark detection with amino acid sensitive reagents. The results indicate that IND/Zn remains effective over longer periods than has been previously demonstrated, although a comparison between documents of different ages suggest that progressive diffusion of the target amino acids occurs over time, affecting the proportion of potentially identifiable marks.The findings of this study reinforce the applicability of IND/Zn for the detection of historic latent fingermarks on old paper documents.

Polymer identity cards are a key target for counterfeit production, posing significant economic and security threats. Examination of suspect identity cards is largely based on visual features, but could potentially exploit diversity in the card composition. This preliminary study investigated the chemical diversity amongst Western Australian driver’s licences using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy with chemometrics. Differences were observed between three series of issue, potentially due to variations in the adhesive or printing materials. Analysis of three licences issued outside of Western Australia also highlighted variations between jurisdictions. This warrants further investigation into the chemical composition of identity cards as a possible tool to assist expert examination.

Science is a public endeavor the results of which are intended to be shared with other scientists, professionals, and the public [1]. This is viewed as a worldwide right: Article 27 of the United Nations Declaration of Human Rights states that ''Everyone has the right to freely participate in the cultural life of the community, to enjoy the arts and to share in scientific advancement and its benefits.'' (United Nations, 1948). The publishing of scientific advancements began in 1665 with Journal des savants and the Philosophical Transactions of the Royal Society. Since then, it is estimated that about 50 million journal articles have been published [2]. At the outset, the idea of publishing scientific results was mocked and created controversy, through difficulties in publishing (like the plague and the Great Fire of London) and scandal (the first editor, Henry Oldenburg, was accused of passing information to an enemy nation while corresponding with a Dutch colleague) [3]. The Royal Society was adamant, however, that science advanced only if a free and open discourse and exploration of ideas, supported by empirical evidence, was allowed. In 2008, the U.S. National Institutes of Health (NIH) mandated that researchers submit final peer-reviewed journal manuscripts to the digital archive PubMed Central no later than 12 months after they had been accepted for publication. Following the European Commission's announcement about open access publishing, the U.S. Office of Science and Technology Policy (OSTP) advised all U.S. funding agencies that spend more than $100 million on external research and development to make publications on supported research freely available online after a suggested 12-month embargo. The Registry of Open Access Repository Mandates and Policies (ROARMAP 2 2 http://roarmap.eprints.org/ . ) provides a searchable international database of agencies with open access requirements. As of February 2019, mandates have been registered by over 700 universities (including Harvard, MIT, Stanford, University College London, and University of Edinburgh) and over 100 research funders worldwide. Scopus

Automotive window tints are commonly applied to motor vehicles to reduce transmittance of light and heat into the interior. They may hence be encountered as physical evidence in criminal investigations, or in civil matters where a tint is suspected to originate from a different source than advertised. Establishing a tint's provenance would be highly relevant in such cases. However, there are currently a lack of established guidelines for forensic tint analysis. This study used attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy with chemometrics to characterize automotive tints based on their adhesive composition. Minimal variability was observed within a single roll of tint, however substantial variability was observed between tints of different brands. Certain individual tint products were also found to possess highly distinctive spectra. Subsequent predictive models were able to associate unknown tint samples to their brand, and found to be robust to both adhesive curing and short-term environmental exposure over a five-month period. The use of ATR-FTIR spectroscopy and chemometrics thus offers a rapid and objective approach to discriminating automotive tints for forensic purposes.

This paper presents a study into the potential of visible spectroscopy with chemometrics as an approach to dating blue ball tip inks on paper documents. Analysis of six inks left under various conditions found that the majority of those kept in the dark could still be matched to the source pen after 32 months of ageing. Conversely, the majority of those exposed to light exhibited rapid spectral changes that continued throughout the 32 month period. Partial least squares regression (PLSR) was used to generate dating models for inks aged with exposure to light. Evaluation using an external test set found absolute dating to be challenging for these ink deposits within the first 2–6 months of ageing. However, predictive accuracy was found to improve for long-term ageing, with two-year old samples yielding age estimates with a maximum error of 6 months. This rapid, non-destructive methodology could assist document examiners in the relative ageing or approximate age determination of questioned documents, as well as the identification of document alterations.

Video spectral comparator (VSC®) workstations are routinely used for visual examinations of pen inks on handwritten documents. Current VSC® models also permit spectral acquisition, which can be combined with chemometric techniques to statistically determine ink similarity. However, there is a lack of research comparing such an approach to typical examinations by forensic experts. This preliminary study compares the analysis of handwritten blue ballpoint inks using visual and spectroscopic analysis. Both approaches were successful in detecting simulated additions or alterations on paper documents. These approaches could thus complement each other as an integrated workflow; providing quantitative data to support expert opinions. Keywords: Forensic science, Questioned documents, Video spectral comparator, Visible spectroscopy, Chemometrics

Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) was utilised to analyse nine differently branded cling films. Principal component analysis (PCA) was used to assess the intra-sample variability, i.e. the variation within individual cling film rolls; as well as the inter-sample variability, which explores the variability between different rolls of cling film. Linear discriminant analysis (LDA) was then employed to develop a predictive classification model which gave 100% correct differentiation between three brand groupings of cling film, and accurately classified all of the validation samples obtained from different rolls from the same manufacturers.

Microspectrophotometry followed by chemometric data analysis was conducted on pairs of visually similar blue acrylic fibers, simulating the “questioned versus known” scenarios often encountered in forensic casework. The relative similarity or dissimilarity of each pair was determined by employing principal component analysis, discriminant analysis and Fisher’s exact test. Comparison of fibers from within each set resulted in a correct inclusion result in 10 out of 11 scenarios, with the one false exclusion attributed to a lack of reproducibility in the spectra. Comparison of fibers from different sets resulted in a correct exclusion result in 108 of 110 scenarios, with two sets that shared identical dye combinations being indistinguishable. Although the presented methods are not infallible, they may nonetheless provide a path forward for forensic fiber examiners that has a more scientifically rigorous basis on which to support their findings in a court of law.

The investigation of explosive events requires appropriate evidential protocols to recover and preserve residues from the scene. In this study, a central composite design was used to determine statistically validated optimum recovery parameters for double-base smokeless powder residues on steel, analysed using total vaporisation (TV) SPME/GC-MS. It was found that maximum recovery was obtained using isopropanol-wetted swabs stored under refrigerated conditions, then extracted for 15 min into acetone on the same day as sample collection. These parameters were applied to the recovery of post-blast residues deposited on steel witness surfaces following a PVC pipe bomb detonation, resulting in detection of all target components across the majority of samples. Higher overall recoveries were obtained from plates facing the sides of the device, consistent with the point of first failure occurring in the pipe body as observed in previous studies. The methodology employed here may be readily applied to a variety of other explosive compounds, and thus assist in establishing ‘best practice’ procedures for explosive investigations.

This study explores the performance of the gold nanoparticle based single metal deposition II (SMD II) technique in developing fingermarks on selected polyethylene surfaces under different environmental conditions in a Western Australian context. Latent fingermarks collected on calcium carbonate/polyethylene blend paper and polyethylene ‘zip-lock’ bags were stored in dry and wet environments for up to 30 days. Useful marks were consistently developed after storage in dry conditions; however, the proportion of useful marks decreased after submersion in water for 30 days. Additionally, background staining on the zip-lock bags had a large impact on the performance of the technique. SMD II was subsequently compared to dry powdering using Lightning Black powder for the detection of latent fingermarks on polyethylene zip-lock bags left in indoor and outdoor environments for up to 4 weeks. SMD II outperformed dry powdering in both environments, showing its potential as a detection technique for latent fingermarks on polyethylene surfaces exposed to environmental conditions.

Counterfeit production of polymer identity cards poses a significant economic cost to society and a threat to national security. Identifying these counterfeits is a challenge for ‘frontline’ personnel who lack training in specialised document examination. This study investigates the use of attenuated total reflectance Fourier Transform infrared (ATR-FTIR) spectroscopy with chemometrics as a potential approach to assessing polymer card authenticity. In situ analysis of several cards found that differentiation could be achieved based on the core polymer composition. A chemometric model was thus built for three driver’s licence series produced in Western Australia and tested using a separate set of seven licences. The majority of test samples were correctly matched to the series of issue, with atypical samples recognisable based on their discriminant values. Synchrotron FTIR imaging revealed that differentiation between each series was possibly related to the adhesive used between the core layers. The approach presented in this work has the potential to be developed as a rapid screening method to identify suspect polymer cards warranting further examination.

Lipstick traces may be encountered in forensic investigations as traces left on clothing, drinkware, tissue papers or other surfaces. However, their probative value is limited by the discriminatory power and destructiveness of existing analysis schemes. This work employed analytical spectroscopy with chemometrics to provide objective and non-destructive characterisation of lipsticks for forensic purposes. 22 red-shaded and 18 nude-shaded lipsticks were analysed using visible absorbance and diffuse reflectance spectroscopy, as well as attenuated total reflectance Fourier transform infrared spectroscopy. Principal component analysis readily distinguished most samples based on their spectral profiles, with subsequent models yielding discrimination accuracies exceeding 94% for each spectroscopic mode. This could provide a greater level of confidence when conducting ‘questioned versus known’ comparisons of similar lipsticks. Further testing using external validation sets produced identification accuracies of 73–100 %, which may allow investigative leads to be more readily obtained from recovered lipstick traces.

35 blue ballpoint inks sourced from Western Australian retailers were deposited onto commercial copy paper and analysed using diffuse reflectance visible spectroscopy. Principal component analysis showed that while several pens were clearly distinguishable based on their visible spectra alone, others exhibited overlap. Linear discriminant analysis was then used to build a chemometric model for the classification of the inks. Using a separate validation set, 71.7% of spectra were correctly assigned to a specific pen, and a further 16.7% to the correct pen supplier. Analysis of six pen inks stored under different conditions found the inks remained chemically stable for at least two months when stored in the dark. However, two inks exhibited spectral changes within one week under ambient light, and all but one ink displayed changes within two months, resulting in altered predictions using the chemometric model. This may be useful in cases of alleged fraud, where it is suspected that an ink entry may have been altered using the same pen at a later date. Artificial ageing experiments found that both heat and ultraviolet light play a role in the ageing process, and that accelerated ageing using these factors gives a reasonable depiction of short-term ageing under natural conditions.

This paper presents a study into the chemical changes occurring within automotive clear coats as a result of environmental weathering, and their potential effect upon the characterisation of samples using infrared spectroscopy combined with chemometric modelling. Testing of three samples, collected from separate vehicles, exposed to the outside environment revealed no changes in model predictions over a 175 day period; however, incorrect predictions were observed following 435 days of exposure. Inspection of the corresponding infrared spectra revealed that these changes were likely due to the hydrolysis and photodegradation of polymer chains present in the clear coat, which were not observed in samples stored away from the outside environment over a one-year period. Analysis of previously weathered samples using synchrotron infrared microscopy found these changes occurred in a top-down fashion rather than within the bulk of the clear coat. This indicates that although weathering may affect the surface characterisation of clear coats over time, the targeting of deeper portions of the clear coat layer may still provide useful information as to the identity of the vehicle.

This paper presents a study into the impact of environmental weathering on the chemometric classification of automotive clear coats. These studies were conducted using attenuated total reflectance infrared spectroscopy, in conjunction with a chemometric model capable of predicting the country of vehicle manufacture for a sample based upon its infrared spectrum. Testing of three samples exposed to environmental conditions found the model to be robust to weathering over at least an eight-month period. However, analysis of 12 samples of unknown prior history found that extreme degradation over at least a 10-year period, or the presence of a post-manufacture (respray) coating, could result in misclassification when relying solely on analysis of the clear coat. It is therefore important that cross-sections comprising the full layer sequence of the paint system are obtained wherever possible, as analysis of the underlying layers may give more comprehensive characterisation.