The use of a silica-based heat sink to “uncouple” the matrix-assisted laser desorption/ionization (MALDI) mechanism

Abstract

The relationships between ion yield(s) as a function of desorption alone and (or) ionization was investigated using two model systems. In the first model system, a carbohydrate (2,3,6-tri-O-methyl-b-cyclodextrin, TMBCD), which could be directly laser desorbed, was analyzed with and without a silicon-based heat sink compound (HSC). The HSC allowed heat to pass through but obstructed the flow of charge. In the second model system, a peptide (substance P), which ccould not be laser desorbed, was analyzed under similar conditions. The ion yield of TMBCD under either system of heat conductivity was similar, whereas the ion yield of the peptide with the heat sink was negligible. Compounds that are predominately cationized either in the gas phase or preformed in solution give an ion yield that is not dependent upon the surface conditions, whereas compounds that are not ordinarily cationized are affected by the emission of electrons from the metal surface.Résumé : Faisant appel à deux systèmes modèles, on a étudié les relations entre les rendements ioniques en fonction de la désorption seule et (ou) de l'ionisation. Dans le premier système modèle, on a analysé un hydrate de carbone, la 2,3,6-tri-O-méthyl-b-cyclodextrine, TMBCD, qui peut être désorbée avec et sans composé dissipateur thermique (CDT) à base de silicone. Le CDT permet la libre circulation de la chaleur, mais obstrue les déplacements de la charge. Dans le deuxième système modèle, on a analysé dans les mêmes conditions un peptide (substance P) qui ne peut pas être désorbé par le laser. Le rendement ionique en TMBCD est semblable quel que soit le système de conductivité thermique alors que le rendement ionique du peptide avec le dissipateur thermique est négligeable. Les composés qui sont d'une façon prédominante cationisés en phase gazeuse ou préformés en solution donnent un rendement ionique qui ne dépend pas des conditions superficielles alors que les composés qui ne sont habituellement pas cationisés sont affectés par l'émission d'électrons par la surface métallique.Mots-clés : dissipateur thermique, désorption laser assistée par la matrice (DLAM), désorption/ionisation assistée par la matrice (DILAM), émission d'électron.[Traduit par la Rédaction]

UV-activated multilayer nanomatrix provides one-step tunable carbohydrate structural characterization in MALDI-MS

“…As shown by our observation above, the silane shell prevents the fragmentation of MNP and functions as a “thermal sink”. 38 On the other hand, the presence of matrix (DHB) molecules augments the ability of the nanoparticles to mediate the energy transfer process and the spontaneous dissociation at high concentration. These properties afford simultaneous ionization and product ion generation, which is not feasible with the free matrix alone (Fig.…”

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2011–2012

“…The ion yields from β‐CD under either system of heat conductivity were found to be similar, whereas the ion yield of the peptide with the heat sink was negligible. It was concluded that compounds that are predominately cationized either in the gas phase or preformed in solution give an ion yield that is not dependent upon the surface conditions, whereas compounds that are not usually cationized are affected by the emission of electrons from the metal surface (Lourantos et al, ).…”