Investigation of colloidal graphite as a matrix for matrix‐assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes

Warren, Alexander; Conway, Ulric; Arthur, Christopher J.; Gates, Paul J.

doi:10.1002/jms.3774

Cited by 14 publications

(20 citation statements)

References 26 publications

(54 reference statements)

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“…This is in accordance with what has previously been observed when comparing graphite matrices to organic matrices. [10][11][12] In negative ion mode analysis, the organic matrices generally performed very poorly (as expected) often with no analyte-related species observed. Spectra were almost totally dominated by the deprotonated ions of the matrices themselves, with little signal resulting from the analytes.…”

Section: Resultssupporting

confidence: 58%

Methodologies for the airbrush application of MALDI matrices

Warren

Mitchell

Gates

2018

Eur J Mass Spectrom (Chichester)

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Keywords:Matrix-assisted laser desorption, matrix, airbrush, colloidal graphite, traditional matrices Dedication:Dedicated to the memory of Professor Peter J. Derrick, who encouraged me to undertake a career in research in mass spectrometry and originally introduced me to MALDI-MS. (Paul Gates 2017). AbstractThere is still a need to develop reliable and robust matrix deposition methods for matrix-assisted laser desorption/ionisation mass spectrometry that are applicable to a range of matrices, solvents and analyte types. This paper presents a robust methodology for the airbrush application of matrices along with the implications of varying the set-up and airbrush parameters. A small number of organic analytes and metal salts are analysed in both positive and negative ion modes to exemplify this methodology. In the analyses with the airbrush deposited matrices, performance was enhanced when compared to standard pipette deposition with the need for a search for sweat spots greatly diminished due to the increase homogeneity of the matrix surface and resultant analyte spots. As expected, the graphite matrices were shown to specifically outperformed the organic matrices in negative ion mode.

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Section: Resultssupporting

confidence: 58%

Methodologies for the airbrush application of MALDI matrices

Warren

Mitchell

Gates

2018

Eur J Mass Spectrom (Chichester)

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“…Carbon based matrices can be effectively employed in MALDI MS experiments 25 ; therefore, it may be speculated that carbon black fingermark enhancement powder could contribute to the ionisation of species contained within the fingermark residue. In order to exclude this possibility , an additional experiment was conducted comparing the MS spectra and the MS images of two halves of the same natural mark, both treated with carbon black though only one half was subsequently sprayed using the MALDI matrix.…”

Section: Throughout the Experiments Performed Usingmentioning

confidence: 99%

Development of operational protocols for the analysis of primary and secondary fingermark lifts by MALDI-MS imaging

2016

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Eight years of intensive research have demonstrated that Matrix-Assisted LaserDesorption/Ionisation Mass Spectrometry Profiling and Imaging (MALDI-MSI and MSP) are powerful tools to gather intelligence around a suspect lifestyle, directly from the identifying ridges of a latent fingermark. In the past three years, many efforts have been invested into translating laboratory methodologies to the field; this was undertaken by devising protocols either for (a) enabling initial fingermark visualisation, such as through the Dry-Wet method, recovery and subsequent MALDI MS based analysis, or for (b) rendering the MS methodologies compatible with the prior application of commonly employed fingermark enhancement techniques (FET). In the present work a major point of interest concerned the sample treatment of FET visualised-lifted fingermarks and the subsequent MS performance of primary tape lifted fingermarks ("primary lifts") versus secondary tape lifted fingermarks (recovery from the surface a second time following the initial primary lift). This was necessary since it may not always be possible to obtain primary lifts of marks visualised at crime scenes for remote MALDI-MSP and MSI. The work illustrated here has provided methodological insights into establishing how to best treat a few types of developed marks in preparation for MALDI-MSI when presented as both secondary and primary lifts; it was demonstrated, as expected, that primary lifts generally yield much higher quality chemical/physical information and are therefore crucial to maximise chances of suspect identification and of retrieval of chemical intelligence. When analysing secondary lifted marks that have been initially developed using aluminium or carbon powders, any of the trialled sample preparation methodologies can be employed except the Dry-Wet method. In the case of TiO 2 powder developed marks, the best ridge coverage was achieved by re-enhancing the mark using the initial powder and spray-coating with MALDI matrix. Primary lifts of fingermarks contaminated with an exogenous substance (used as a reference model) yielded the best ridge detail quality whilst for secondary lifts of natural marks pre-enhanced with aluminium powder, significantly greater intensity of the ion image was observed for the sections subjected to either no further enhancement or re-enhancement using aluminium powder.Keywords: Fingermarks; MALDI; Imaging; powders; lifts IntroductionWhile successful academic research is paramount for scientific progress, it is its translational feasibility that enables the impact of this research in the real world. With this view in mind, these authors are actively pursuing the development of protocols enabling MALDI-MS based technologies, with particular focus on the imaging modality, to be implemented into the current fingerprinting workflow.The pioneering development of MALDI-MS methodologies in fingermark analysis has a short but strong track record history of success, demonstrating the opportunity to retrieve additional devising an ...

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“…This demonstrates that flavone is a more effective matrix than the 'traditional' across the range of matrices tested, is given in The use of CG as a matrix for LMW MALDI has already been studied extensively by the authors' research group. 19 In this study, the peaks observed in the positive ion mode with CG were dominated by the singly charged naked metal cations, cation oxides and carbides. nor which anion is present.…”

Section: Resultsmentioning

confidence: 59%

Flavone as a novel matrix for the matrix‐assisted laser desorption/ionisation analysis of lanthanide and transition metal salts

Warren

Gates

2020

J Mass Spectrom

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The mass spectral analysis of metal salts, especially lanthanide and transition metal salts, can be challenging. Although getting information on the metal present is usually straightforward, obtaining information on the correct oxidation state and anion composition is challenging. Many ionisation techniques have some redox component to the ionisation process, which commonly results in changing the oxidation state of the metal and the associated loss of ligand and anion information. We present here a simple method for negative ion matrix-assisted laser desorption/ionisation mass spectrometry using the non-acidic flavonoid flavone as a novel matrix. This results in reliable information on the oxidation state of the metal as spectra are dominated by anion adduct ions with very little (typically no) redox processes occurring.

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Investigation of colloidal graphite as a matrix for matrix‐assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes

Cited by 14 publications

References 26 publications

Methodologies for the airbrush application of MALDI matrices

Methodologies for the airbrush application of MALDI matrices

Development of operational protocols for the analysis of primary and secondary fingermark lifts by MALDI-MS imaging

Flavone as a novel matrix for the matrix‐assisted laser desorption/ionisation analysis of lanthanide and transition metal salts

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