Reversing microcrystalline tests: an analytical approach to recycling of microcrystals from drugs of abuse

A combined analysis of microcrystalline tests followed by LC-MS or GC-MS analysis is described. Microcrystalline tests are shown to be non-destructive as addition products formed were easily dissociated after the application of an appropriate solvent. Subsequent analysis of the sample was done to quantify the recovery of the drug. Examples were performed using the date rape drug γ-hydroxybutyrate (GHB) and the synthetic opioid methadone

Enhancing the student learning experience through memes

Meme-making is an effective method for engaging students and enhancing the learning environment. Memes are a social media cultural phenomenon that the majority of those in Higher Education are exposed to on an almost daily occurrence. This research examined the use of meme-making within the forensic sciences to allow students to reflect on their knowledge. Students studying modules in forensic science across six universities in the UK and USA participated in the study. At the end of a teaching session, students produced a meme (using Meme Generator) to reflect on what they had learned; memes were then shared with the class anonymously via Padlet. This allowed all class members to see and engage with the memes created. At the end of the activity students were anonymously surveyed on their experience using Microsoft Forms and analysis of the results were undertaken using SPSS software.Meme-making was found to be an inclusive learning activity with no limitations, including age (part-time, distance learning and visually impaired students were not part of the study parameters). Results showed that not only did students find the practice fun, but it also helped with the retention of the class content suggesting that the meme-making process is an effective way to enhance the learning environment while engaging students.Student feedback suggests that to maximise participation the educator should stress reflection and learning as the key purpose of generating a meme, rather than being witty or entertaining. The forensic science educator should be mindful of selecting appropriate subject matter for this often-humorous activity

Variation in amino acid and lipid composition of latent fingerprints

The enhancement of latent fingerprints, both at the crime scene and in the laboratory using an array of chemical, physical and optical techniques, permits their use for identification. Despite the plethora of techniques available, there are occasions when latent fingerprints are not successfully enhanced. An understanding of latent fingerprint chemistry and behaviour will aid the improvement of current techniques and the development of novel ones. In this study the amino acid and fatty acid content of ‘real’ latent fingerprints collected on a non-porous surface was analysed by gas chromatography–mass spectrometry. Squalene was also quantified in addition. Hexadecanoic acid, octadecanoic acid and cis-9- octadecenoic acid were the most abundant fatty acids in all samples. There was, however, wide variation in the relative amounts of each fatty acid in each sample. It was clearly demonstrated that touching sebum-rich areas of the face immediately prior to fingerprint deposition resulted in a significant increase in the amount of fatty acids and squalene deposited in the resulting ‘groomed’ fingerprints. Serine was the most abundant amino acid identified followed by glycine, alanine and aspartic acid. The significant quantitative differences between the ‘natural’ and ‘groomed’ fingerprint samples seen for fatty acids were not observed in the case of the amino acids. This study demonstrates the variation in latent fingerprint composition between individuals and the impact of the sampling protocol on the quantitative analysis of fingerprints

Animals can assign novel odours to a known category

The ability to identify a novel stimulus as a member of a known category allows an organism torespond appropriately towards it. Categorisation is thus a fundamental component of cognition andan essential tool for processing and responding to unknown stimuli. Therefore, one might expectto observe it throughout the animal kingdom and across sensory domains. There is much evidenceof visual categorisation in non-human animals, but we currently know little about this process inother modalities. In this experiment, we investigated categorisation in the olfactory domain. Dogswere trained to discriminate between 40 odours; the presence or absence of accelerants formed thecategorical rule. Those in the experimental group were rewarded for responding to substrates withaccelerants (either burnt or un-burnt) and inhibit responses to the same substrates (either burnt or unburnt)without accelerants (S+ counterbalanced). The pseudocategory control group was trained onthe same stimuli without the categorical rule. The experimental group learned the discrimination andanimals were able to generalise to novel stimuli from the same category. None of the control animalswere able to learn the discrimination within the maximum number of trials. This study provides the firstevidence that non-human animals can learn to categorise non-biologically relevant odour information

Enhancing the student learning experience through memes

Meme-making is an effective method for engaging students and enhancing the learning environment. Memes are a social media cultural phenomenon that the majority of those in Higher Education are exposed to on an almost daily occurrence. This research examined the use of meme-making within the forensic sciences to allow students to reflect on their knowledge. Students studying modules in forensic science across six universities in the UK and USA participated in the study. At the end of a teaching session, students produced a meme (using Meme Generator) to reflect on what they had learned; memes were then shared with the class anonymously via Padlet. This allowed all class members to see and engage with the memes created. At the end of the activity students were anonymously surveyed on their experience using Microsoft Forms and analysis of the results were undertaken using SPSS software. Meme-making was found to be an inclusive learning activity with no limitations, including age (part-time, distance learning and visually impaired students were not part of the study parameters). Results showed that not only did students find the practice fun, but it also helped with the retention of the class content suggesting that the meme-making process is an effective way to enhance the learning environment while engaging students. Student feedback suggests that to maximise participation the educator should stress reflection and learning as the key purpose of generating a meme, rather than being witty or entertaining. The forensic science educator should be mindful of selecting appropriate subject matter for this often-humorous activity

Evaluation of the dimethylaminocinnemaldehyde contact transfer process and its application to fingerprint development on thermal papers

The use of dimethylaminocinnemaldehyde (DMAC) as a fingerprint development reagent was first proposed in the 1970s as a solution-dipping technique to target the urea constituent of fingerprints. However, in operational trials, the quality of developed fingerprints was poor. This was attributed to diffusion of urea with time, and the technique was not pursued. More recently, the use of DMAC fuming and the use of sheets impregnated with DMAC solution have been proposed as alternative fingerprint development processes for porous surfaces, in particular for thermal papers. This study reports an analysis of the DMAC development process using impregnated paper sheets and compares its effectiveness to other techniques proposed for thermal papers. The study concludes that the DMAC transfer process primarily targets amino acids in the fingerprint, but that these may be less persistent than the constituents targeted by ninhydrin and DFO; consequently, the effectiveness decreases more rapidly as the fingerprints age. Overall, the most effective process for thermal papers if it is not necessary to retain the text is an ethanol pre-dip followed by DFO

Evaluation of the dimethylaminocinnemaldehyde contact transfer process and its application to fingerprint development on thermal papers

The use of dimethylaminocinnemaldehyde (DMAC) as a fingerprint development reagent was first proposed in the 1970s as a solution-dipping technique to target the urea constituent of fingerprints. However, in operational trials, the quality of developed fingerprints was poor. This was attributed to diffusion of urea with time, and the technique was not pursued. More recently, the use of DMAC fuming and the use of sheets impregnated with DMAC solution have been proposed as alternative fingerprint development processes for porous surfaces, in particular for thermal papers. This study reports an analysis of the DMAC development process using impregnated paper sheets and compares its effectiveness to other techniques proposed for thermal papers. The study concludes that the DMAC transfer process primarily targets amino acids in the fingerprint, but that these may be less persistent than the constituents targeted by ninhydrin and DFO; consequently, the effectiveness decreases more rapidly as the fingerprints age. Overall, the most effective process for thermal papers if it is not necessary to retain the text is an ethanol pre-dip followed by DFO

Chemical Characterization of Latent Fingerprints by Matrix-Assisted Laser Desorption Ionization, Time-of-Flight Secondary Ion Mass Spectrometry, Mega Electron Volt Secondary Mass Spectrometry, Gas Chromatography/Mass Spectrometry, X‑ray Photoelectron Spectroscopy, and Attenuated Total Reflection Fourier Transform Infrared Spectroscopic Imaging: An Intercomparison

The first analytical intercomparison of fingerprint residue using equivalent samples of latent fingerprint residue and characterized by a suite of relevant techniques is presented. This work has never been undertaken, presumably due to the perishable nature of fingerprint residue, the lack of fingerprint standards, and the intradonor variability, which impacts sample reproducibility. For the first time, time-of-flight secondary ion mass spectrometry, high-energy secondary ion mass spectrometry, and X-ray photoelectron spectroscopy are used to target endogenous compounds in fingerprints and a method is presented for establishing their relative abundance in fingerprint residue. Comparison of the newer techniques with the more established gas chromatography/mass spectrometry and attenuated total reflection Fourier transform infrared spectroscopic imaging shows good agreement between the methods, with each method detecting repeatable differences between the donors, with the exception of matrix-assisted laser desorption ionization, for which quantitative analysis has not yet been established. We further comment on the sensitivity, selectivity, and practicability of each of the methods for use in future police casework or academic research

Chemical Characterization of Latent Fingerprints by Matrix-Assisted Laser Desorption Ionization, Time-of-Flight Secondary Ion Mass Spectrometry, Mega Electron Volt Secondary Mass Spectrometry, Gas Chromatography/Mass Spectrometry, X‑ray Photoelectron Spectroscopy, and Attenuated Total Reflection Fourier Transform Infrared Spectroscopic Imaging: An Intercomparison

The first analytical intercomparison of fingerprint residue using equivalent samples of latent fingerprint residue and characterized by a suite of relevant techniques is presented. This work has never been undertaken, presumably due to the perishable nature of fingerprint residue, the lack of fingerprint standards, and the intradonor variability, which impacts sample reproducibility. For the first time, time-of-flight secondary ion mass spectrometry, high-energy secondary ion mass spectrometry, and X-ray photoelectron spectroscopy are used to target endogenous compounds in fingerprints and a method is presented for establishing their relative abundance in fingerprint residue. Comparison of the newer techniques with the more established gas chromatography/mass spectrometry and attenuated total reflection Fourier transform infrared spectroscopic imaging shows good agreement between the methods, with each method detecting repeatable differences between the donors, with the exception of matrix-assisted laser desorption ionization, for which quantitative analysis has not yet been established. We further comment on the sensitivity, selectivity, and practicability of each of the methods for use in future police casework or academic research