Ion trap MSn genealogical mapping?approaches for structure elucidation of novel products of consecutive fragmentations of morphinans

Strife, Robert J.; Robosky, Lora C.; Garrett, Garry; Ketcha, M. M.; Shaffer, J. D.; Zhang, Nan

doi:10.1002/(sici)1097-0231(20000229)14:4<250::aid-rcm865>3.0.co;2-9

Cited by 9 publications

(4 citation statements)

References 13 publications

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“…The corresponding ions in the STX spectrum at m/z 204 (204a) and m/z 179 (Scheme 2) therefore did not exhibit comparable radical ⅐OH losses, as STX does not have a hydroxyl group at N-1. Similar even-electron to odd-electron switches at higher stages of MS n were observed by Strife and coworkers [52] in their analysis of morphinane derivatives because the corresponding species lacked other favorable fragmentation pathways. Interestingly, the NEO species 237b and 195b can further rearrange to 237a or 195a via hydroxyl transfer from N-1 to C-13 (m13; Schemes 3b and 5).…”

Section: Dissociation Pathways and Mechanismssupporting

confidence: 74%

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Gas-phase dissociation reactions of protonated saxitoxin and neosaxitoxin

Sleno

Volmer

Kovačević

et al. 2004

J. Am. Soc. Mass Spectrom.

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The aim of this study was to investigate the behavior of the protonated paralytic shellfish poisons saxitoxin (STX) and neosaxitoxin (NEO) in the gas-phase after ion activation using different tandem mass spectrometry techniques. STX and NEO belong to a group of neurotoxins produced by several strains of marine dinoflagellates. Their chemical structures are based on a tetrahydropurine skeleton to which a 5-membered ring is fused. STX and NEO only vary in their substituent at N-1, with STX carrying hydrogen and NEO having a hydroxyl group at this position. The collision-induced dissociation (CID) spectra exhibited an unusually rich variety and abundance of species due to the large number of functional groups within the small skeletal structures. Starting with triple-quadrupole CID spectra as templates, linked ion-trap MSn data were added to provide tentative dissociation schemes. Subsequent high-resolution FTICR experiments gave exact mass data for product ions formed via infrared multiphoton dissociation (IRMPD) from which elemental formulas were derived. Calculations of proton affinities of STX and NEO suggested that protonation took place at the guanidinium group in the pyrimidine ring for both molecules. Most of the observed parallel and consecutive fragmentations could be rationalized through neutral losses of H2O, NH3, CO, CO2, CH2O and different isocyanate, ketenimine and diimine species, many of which were similar for STX and NEO. Several exceptions, however, were noted and differences could be readily correlated with reactions involving NEO's additional hydroxyl group. A few interesting variations between CID and IRMPD spectra are also highlighted in this paper.

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Section: Dissociation Pathways and Mechanismssupporting

confidence: 74%

“…As demonstrated by Strife et al [52], ion-trap genealogical information can be added to QqQ CID spectra, where the QqQ spectra serve as initial templates for structure elucidations. We have taken a similar approach in this study.…”

Section: Collisional Activation Of the Protonated Moleculesmentioning

confidence: 99%

Gas-phase dissociation reactions of protonated saxitoxin and neosaxitoxin

Sleno

Volmer

Kovačević

et al. 2004

J. Am. Soc. Mass Spectrom.

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“…This is most likely due to difficulties associated with characterizing the MALDI‐MS fragments. Unlike the step‐wise fragmentation or genealogical mapping17 possible with ion traps where the losses observed are generally very limited and the sequence of fragmentation is known, MALDI often produces fragments that are a result of multiple cleavages making structural assignment of these fragments much more time‐consuming, problematic, and sometimes less trustworthy. As a result, the increased number of low mass fragments observed with MALDI‐MS ( m/z < 200) relative to ion‐trap MS are often not identified.…”

Section: Resultsmentioning

confidence: 99%

An experimental comparison of electrospray ion‐trap and matrix‐assisted laser desorption/ionization post‐source decay mass spectra for the characterization of small drug molecules

LeRiche¹,

Osterodt²,

Volmer³

2001

Rapid Comm Mass Spectrometry

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An experimental comparison of product ion spectra produced by matrix-assisted laser desorption/ionization (MALDI) and electrospray ion-trap MS( n) for a group of small drug molecules is presented in this paper. The goal of the study was to demonstrate the usefulness of MALDI-MS with post-source decay (PSD) and collision-induced dissociation (CID) for the structural analysis of small drug molecules in the drug discovery process, where traditionally electrospray LC/MS methods are used. PSD and PSD/CID gave diverse product ions that were highly indicative of the structure of the drugs investigated (a group of 4-quinolone antibiotics and oleandomycin). In addition, the number of different product ions generated with MALDI-MS was always higher than with electrospray ion-trap MS( n) (with n < or =4) for the drug molecules studied. This investigation also showed that the choice of a suitable MALDI matrix for the analysis of low molecular weight compounds is quite important. It was found that of the three matrices examined, alpha-cyano-4-hydroxycinnamic acid (alpha-CHCA) produced the most intense fragmentation levels while TiO2, with its advantage of virtually no low mass background signals, did not generate quite the same amount of information.

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“…A powerful tool in elucidating fragmentation mechanisms is the ion trap, which allows step-wise and controlled fragmentation in multiple-stage MS-MS. A nice and recent example of its potential is demonstrated in the elucidation of the fragmentation pattern of dextromethorphan and some of its metabolites [12].…”

Section: Progress In Mass Spectrometry Instrumentationmentioning

confidence: 99%

Structure elucidation by LC-MS. Foreword

Niessen¹

2000

Analusis

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The topic of this Analusis Dossier is structure elucidation by liquid chromatography -mass spectrometry (LC-MS). When LC-MS first came along in the mid 1970's [1], one of the incentives and objectives was to develop a technique similar to the very successful gas chromatography -mass spectrometry (GC-MS), but capable of identifying especially those components which were not amenable to GC-MS. To that end, interfaces were developed, aiming at the application of electron ionisation (EI), like in GC-MS. Although these interfaces like the moving-belt and the particle-beam interface actually demonstrated that the applicability range of EI could be significantly extended, ironically enough these two interfaces did not achieved the major breakthroughs in the development of LC-MS.Major steps in the history of LC-MS were made using interfaces that only allow soft ionisation techniques, resulting in (de)protonated molecules with little or no fragmentation. Thermospray interfacing from the mid 1980 onwards for the first time gave a glimpse on what LC-MS could really do. With the broad implementation of the atmospheric-pressure ionization and interfacing, viz. (pneumatically-assisted) electrospray ionisation and interfacing (ESI) and the heated nebuliser in combination with atmosphericpressure chemical ionisation (APCI), LC-MS became a powerful technique which could even be used by less experienced people. However, in addition, the most frequent use of LC-MS today is quite different from the initial objective indicated above. LC-MS has significantly changed the impact of MS in a laboratory, because with LC-MS the mass spectrometer has entered both laboratories and application areas in a way which was certainly not foreseen at the beginning of its history in the mid 1970's [2]. Especially the large interest in routine quantitative analysis and peptide and protein analysis was not anticipated.With LC-MS being based on soft ionisation techniques, the development of LC-MS to some extent stimulated the developments in tandem mass spectrometry, especially in triple-quadrupole and ion-trap instruments. With the ability to fragment the even-electron protonated or deprotonated ions, generated in ESI and APCI, by means of collisioninduced dissociation (CID), the first steps in the direction to structure elucidation could be made. However, soon it was realised that in fact there is far less knowledge on the fragmentation of these even-electron ions compared to that of odd-electron ions [3], as generated in EI. Despite the fact that many authors tried and still try to cover this by incorrectly calling the (de)protonated molecule a '(de)protonated molecular ion ' [4], this difference is obvious and important when one starts to interpret the MS-MS product-ion mass spectra. In addition, the interpretation of the product-ion mass spectra must actually be performed, because no spectral libraries were available which could be used to assist in the structure elucidation. Fragmentation of even-electron ionsIn the past 14 years, ever since my pr...

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Ion trap MSn genealogical mapping?approaches for structure elucidation of novel products of consecutive fragmentations of morphinans

Cited by 9 publications

References 13 publications

Gas-phase dissociation reactions of protonated saxitoxin and neosaxitoxin

Gas-phase dissociation reactions of protonated saxitoxin and neosaxitoxin

An experimental comparison of electrospray ion‐trap and matrix‐assisted laser desorption/ionization post‐source decay mass spectra for the characterization of small drug molecules

Structure elucidation by LC-MS. Foreword

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