Abstract
RationaleSALDI-MS (Surface-Assisted Laser Desorption/Ionisation Mass Spectrometry) is an approach derived from MALDI-MS (Matrix-Assisted Laser Desorption/Ionisation) which overcomes the drawbacks associated with the use of organic matrices required to co-crystallize with the analytes. Indeed, nanomaterials commonly used in SALDI-MS as inert surfaces to promote desorption/ionization (D/I) ensure straightforward direct deposition of the samples while providing mass spectra with ions only related to the compound of interest. The objective of this study is to develop a novel SALDI-MS approach based on steel plates that are surfaces very rapidly and easily tuned to perform the most efficient peptide detection as possible. To compare the SALDI efficacy of such metal substrates, D/I efficiency and deposit homogeneity will be evaluated according to steel plate fabrication processes.MethodThe studied surfaces are nanostructured steel plates that were chemically modified by perfluorosilane and textured according to different frequencies and laser writing powers. The capacity of each tested 100 surfaces was demonstrated by the comparative analyzes of a mixture of standard peptides (m/z 600 – 3000) performed with a MALDI-TOF instrument enabling MALDI, SALDI and Imaging experiments.ResultsA peptide mix was used to screen the different surfaces depending on their D/I efficiency and their ability to ensure homogeneous deposit of the samples. In that purpose, deposition homogeneity was visualized owing to reconstructed ionic images from all protonated or sodiated ions of the 10 peptides constituting the standard mix.ConclusionSeven surfaces were then selected satisfying the required D/I efficiency and deposit homogeneity criteria. Results obtained with these optimal surfaces were then compared with those recorded by MALDI-MS analyses used as references.