Optimization of Sample Preparation and Instrumental Parameters for the Rapid Analysis of Drugs of Abuse in Hair samples by MALDI-MS/MS Imaging

Abstract

Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) has been employed to rapidly screen longitudinally sectioned drug user hair samples for cocaine and its metabolites using continuous raster imaging. Optimization of the spatial resolution and raster speed were performed on intact cocaine contaminated hair samples. The optimized settings (100 × 150 μm at 0.24 mm/s) were subsequently used to examine longitudinally sectioned drug user hair samples. The MALDI-MS/MS images showed the distribution of the most abundant cocaine product ion at m/z 182. Using the optimized settings, multiple hair samples obtained from two users were analyzed in approximately 3 h: six times faster than the standard spot-to-spot acquisition method. Quantitation was achieved using longitudinally sectioned control hair samples sprayed with a cocaine dilution series. A multiple reaction monitoring (MRM) experiment was also performed using the ‘dynamic pixel’ imaging method to screen for cocaine and a range of its metabolites, in order to differentiate between contaminated hairs and drug users. Cocaine, benzoylecgonine, and cocaethylene were detectable, in agreement with analyses carried out using the standard LC-MS/MS method. Graphical Abstractᅟ Electronic supplementary materialThe online version of this article (doi:10.1007/s13361-017-1766-0) contains supplementary material, which is available to authorized users.

Criminal profiling through MALDI MS based technologies – breaking barriers towards border-free forensic science

“…Incidentally, this is also why, another application stream concerns the detection and mapping of drugs of abuse and metabolites in a single hair by MALDI MSI. This analysis exhibits numerous advantages over the gold standard in use and it is being developed by Sheffield Hallam University UK and M4I in the Netherlands [20][21] . (the presence of many proteins).…”

Emerging applications in mass spectrometry imaging; enablers and roadblocks

“…This group, from the Netherlands, then also successfully demonstrated an approach using multiple-reaction monitoring (MRM) to detect metabolites in hair sections differentiating between cocaine users and externally contaminated hair. 8 This is a benefit unique to MSI, which can simultaneously perform MRM and provide the visual distribution of the exact location of these analytes ( Figure 4). Analysis of the hair samples took around 3 h compared to the current methodology which takes 1 h; however, sample preparation for the current methodology takes around 1 day, whilst MALDI-MS sample preparation is 1 h, thus indicating a significantly higher overall speed of hair processing using MALDI-MSI.…”

“…Since its development for biomolecular imaging by the Caprioli group in 1997, 1 MSI has established itself to encapsulate many bioanalytical applications, analysing a variety of samples including single-cells, three-dimensional cultures, animal tissues, whole rodents, patient microarrays and biopsies, fingermarks, and human hair. [2][3][4][5][6][7][8] Over the last decade, technical advancements in instrumentation have allowed vast improvements in MSI speed, spatial resolution and sensitivity. In addition, MSI modalities employing a wide range of ionisation sources have been developed including: matrix-assisted laser desorption ionisation (MALDI), a soft ionisation technique which employs laser energy and an absorbing matrix; secondary ionisation mass spectrometry (SIMS), using a focused primary beam of ions resulting in the analysis of secondary ions ejected from the sample surface; desorption electrospray ionisation (DESI), an ambient ionisation methodology via a solvent spray; laser ablation inductively coupled plasma (LA-ICP) involves a nanosecond-pulsed laser to the sample surface; and liquid extraction surface analysis (LESA) via direct micro-junction solvent extraction.…”

New Advances in Toxicological Forensic Analysis Using Mass Spectrometry Techniques

“…Therefore, these methods are important when the imaging information on drug distribution is necessary, for example, in human hair without extensive sample preparation, or when labelling techniques are required. However, it should be noted that it only provides qualitative data about administered drugs, through a pixelated representation [ 38 ]. MALDESI has also been coupled with HRMS during the identification of 74 drug samples which were detected using the ionic liquid matrix N,N diisopropylethylammonium α -cyanohydroxycinnamate.…”