A fast atom bombardment and matrix‐assisted laser desorption/ionization mass spectrometry study of doubly charged porphyrins

Abstract

In this mass spectrometry (MS) study of doubly charged porphyrin salts, fast atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) MS techniques are utilized to examine several unique ionic species. The predominant transformation of preformed doubly charged ions in the desorption/ionization mechanism of FAB and MALDI is the result of deprotonation reactions to form singly charged ions of the type [M(2+) - H(+)](+) and of one-electron reductions to form radical cations [M(2+) + e(-)](+.). The dependence of this phenomenon and the formation of a number of additional ionic species on the different matrices and the FAB-matrix additive benzoquinone is examined. The significant analogous behavior of doubly charged porphyrins in FAB- and MALDI-MS leads to the conclusion that one-electron reductions are of distinct relevance in the desorption/ionization mechanism of MALDI.

A MALDI-MSI Approach to the Characterization of Radiation-Induced Lung Injury and Medical Countermeasure Development

“…Synthetic cationic porphyrins have been shown to produce multiple different ions depending on the ionization source used for analysis, and their structure, metal complex, and counter ions(Batinić-Haberle et al 2000, Schäfer and Budzikiewicz 2001, Ramos et al 2008). These can include but are not limited to, deprotonation, one to four electron reduction of the cations, loss of the metal complex, loss of alkyl groups, and matrix adduct/complex formation (MALDI/fast atom bombardment (FAB))(Batinić-Haberle et al 2000, Kachadourian et al 2001, Schäfer and Budzikiewicz 2001, Ramos et al 2008, Ramos et al 2014). The ion at m/z 1008 was the most abundant peak in all spectra acquired and arises from a DHB adduct of the compound without the chloride salts.…”

Comparison of the sensitivity of mass spectrometry atmospheric pressure ionization techniques in the analysis of porphyrinoids

“…Porphyrinoids are characterized by a great variety of structure types; hence, it is not possible to analyze them by using only one ionization method. There are many examples in the literature regarding the application of various MS ionization techniques [EI, [2,3] chemical ionization (CI), [4,5] electrospray ionization (ESI), [6][7][8][9][10][11] atmospheric pressure CI (APCI), [12][13][14] atmospheric pressure photoionization (APPI), [15][16][17][18] fast atom bombardment (FAB), [19][20][21] liquid secondary ion MS, [22,23] field desorption, [24][25][26] matrix-assisted laser desorption/ionization (MALDI) [19,27,28] ] with reference to this class of compounds. It is also possible to find examples of comparison of ionization methods in qualitative terms, but the number of such publications is very limited.…”

Evaluation of the reduction of imidazophenazine dye derivatives under fast‐atom‐bombardment mass‐spectrometric conditions

“…Since a lot of previous studies in the early days of FAB have concerned the reduction process of various organic and inorganic compounds under particle bombardment conditions,1–4, 16–37 our first task was to summarize the available literature information. In this, we focused our attention mainly on aromatic heterocyclic compounds bearing structural similarity with the systems investigated in the present work.…”