A Chemist's Paradise

Evaluating the Bleeding Effect in DESI-MSI Molecular Fingerprinting

My third PhD paper Since its inception in 2004, Desorption Electrospray Ionization Mass Spectrometry (DESI MS) has seen a significant increase in its application to the pharmaceutical and clinical setting, supported by a steady improvement of the sensitivity, mass accuracy, mass resolution, spatial resolution and usability, as well as by the advantages offered by its ambient nature. However, in comparison to the rapid growth for tissue imaging, the uptake of DESI-MSI in fingerprint imaging has not grown a substantial body of knowledge, compared to MALDI-MSI. In this work, we set off to dissect the application of DESI-MSI to fingerprint imaging to explore both the advantages and the potential challenges that might have slowed the uptake, taking stock from our previous work and that of others in this area. During this endeavor we have highlighted advantages but also discovered that, under a range of optimized operating conditions, fingerprint imaging by DESI-MSI is affected by a delocalization phenomenon which we termed “the bleeding effect”. This phenomenon has been shown to be specific to fingerprints, as sample type, as opposed to biological tissues, and may be one of the contributing factors to a seemingly slower uptake of this technique in molecular fingerprinting. Therefore, a description of the observed effect, how to minimize it, and its implications in operational work are discussed. https://doi.org/10.1021/acs.analchem.5c08143

Multimodal MSI for Drug Analysis on Fingerprints

My Second PhD Paper Although drug facilitated sexual assault (DFSA) is an old issue, current statistics on the frequency of this crime have led to growing concerns. As these drugs are metabolised very quickly, toxicological evidence from biological fluids, corroborating the victim's statement, is challenging to recover, especially with late reports. We are proposing an additional method involving the analysis of the victim's fingermarks recovered at the scene(s) of the crime, which may contain the parent drug and its metabolite. As a case study, a multi-modal mass spectrometry-based approach has been developed and explored to detect and image both risperidone and its pharmacologically active metabolite, paliperidone, after contamination of a fingertip at very low concentrations and deposition of a fingerprint on a surface. In particular Matrix Assisted Laser Desorption Ionisation Mass Spectrometry Imaging (MALDI MSI), Desorption Electrospray Ionisation Mass Spectrometry Imaging (DESI MSI) and Soft Ionisation by Chemical Reaction In Transfer, (SICRIT®) have been used in different combinations to both detect the drugs and reconstruct the fingerprint ridge pattern; this approach enables the simultaneous provision of both chemical information (circumstances surrounding the crime) and biometric information. A forensic operational scenario has also been simulated whereby the contaminated fingerprint is deposited on paper and enhanced with a routine fingerprint enhancement technique prior to analysis via mass spectrometry imaging. Overall, our investigation indicates that this additional approach is feasible and is worth exploring further.Check the paper out: https://doi.org/10.1039/D5AN00328H [https://doi.org/10.1039/D5AN00328H]

Fingerprints and Mass spectrometry

Matrix-AssistedLaser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI) has become acritical tool for biometric and lifestyle analysis through fingermarks,significantly aiding police investigations. Pioneered by Sheffield HallamUniversity and the Francese group, this technique revolutionizes chemicalfingerprint analysis by providing detailed molecular information and visualisingmultiple fingermark images. Our researchexplores the applications of MALDI-MSI using the state-of-the-art SELECT SERIESMALDI-MRT (Multi-Reflecting Time-of-Flight) mass spectrometer, which featuresexceptional mass measurement accuracy (sub-ppm) and spatial resolution (15 µm)in detecting and visualising various antipsychotics, date rape drugs, and otherforensic markers within latent fingermarks. The complexity of this state-of-the art mass spectrometerand it being the ever first installed instrument of this type in the UK,required very careful and non-trivial setting optimisation to maximise thesystem’s performance. Podcast created using Google NotebookLMResearch paper: https://doi.org/10.1016/j.aca.2025.343998 [https://doi.org/10.1016/j.aca.2025.343998]

The Brain on Drugs

This episode talks about how the personality of an individual is affected by drugs and different concepts in psychology and chemistry!

Mental Health in Science

Hello fellow humans, In this episode, I talk about mental health in the scientific community and if you should publish or perish!