A comparative computational study of matrix-peptide interactions in MALDI mass spectrometry: the interaction of four tripeptides with the MALDI matrices 2,5-dihyroxybenzoic acid, α-cyano-4-hydroxy-cinnamic acid and 3,5-dihyroxybenzoic acid

Ueno‐Noto, Kaori

doi:10.1080/00268970802637828

Cited by 4 publications

(1 citation statement)

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“…Variations of experimentally accessible parameters such as, e.g., laser fluence and irradiation wavelength as well as matrix and analyte properties led to a large variety of proposals and partial aspects regarding the underlying processes [2,. For closer insights, the physicochemical reactions taking place were elucidated by determination of the gas phase basicities as well as proton and electron affinities of the involved matrix [29][30][31][32][33][34][35][36] and analyte [37][38][39][40][41][42][43] neutral and ion species and were complemented by theoretical considerations and computational chemistry [34,[44][45][46][47][48][49]. From these investigations, two conflicting theories predominantly discussed nowadays emerged: The Lucky Survivor theory [17,50] and the gas phase protonation model [5,16,24,28,51].…”

Section: Introductionmentioning

confidence: 99%

Compelling Evidence for Lucky Survivor and Gas Phase Protonation: The Unified MALDI Analyte Protonation Mechanism

Jaskolla

Karas

2011

J. Am. Soc. Mass Spectrom.

166

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This work experimentally verifies and proves the two long since postulated matrix-assisted laser desorption/ionization (MALDI) analyte protonation pathways known as the Lucky Survivor and the gas phase protonation model. Experimental differentiation between the predicted mechanisms becomes possible by the use of deuterated matrix esters as MALDI matrices, which are stable under typical sample preparation conditions and generate deuteronated reagent ions, including the deuterated and deuteronated free matrix acid, only upon laser irradiation in the MALDI process. While the generation of deuteronated analyte ions proves the gas phase protonation model, the detection of protonated analytes by application of deuterated matrix compounds without acidic hydrogens proves the survival of analytes precharged from solution in accordance with the predictions from the Lucky Survivor model. The observed ratio of the two analyte ionization processes depends on the applied experimental parameters as well as the nature of analyte and matrix. Increasing laser fluences and lower matrix proton affinities favor gas phase protonation, whereas more quantitative analyte protonation in solution and intramolecular ion stabilization leads to more Lucky Survivors. The presented results allow for a deeper understanding of the fundamental processes causing analyte ionization in MALDI and may alleviate future efforts for increasing the analyte ion yield.

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