Desorption chemical ionization, thermospray, and fast atom bombardment mass spectrometry of dihydropyridine .dblharw. pyridinium salt-type redox systems

Prókai, László; Hsu, Bih Hsiung.; Farag, H.A.; Bodor, Nicholas

doi:10.1021/ac00190a026

Cited by 23 publications

(7 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Quaternary ammonium salts are popular test compounds that have been studied by various soft mass spectrometric techniques,1–10 since the presence of fixed ‘preformed’ charges in their organic cations facilitates investigations on the fundamentals of ion generation and on fragmentation pathways. In our previous studies11–17 we selected the bisquaternary ammonium compound decamethoxinum as a structure and energy probe for soft ionization methods, because it demonstrated a strong dependence of the types of ions recorded in the mass spectra on the mass spectrometric technique and experimental conditions applied.…”

mentioning

confidence: 99%

The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum

Pashynska

Kosevich

Heuvel

et al. 2006

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

The effect of cone voltage (CV) variation on the mass spectral pattern of the bisquaternary ammonium salt decamethoxinum in the electrospray ionization (ESI) mode was studied. The advantage of decamethoxinum as a test compound in ESI mass spectrometry lies in the production of two types of precursor ions, i.e. the doubly charged organic dication Cat 2R and its singly charged cluster with a Cl S counterion, Cat Á Cl R . This makes it possible to monitor the fragmentation patterns of these ions under identical experimental conditions. Pronounced qualitative and quantitative changes in the ESI mass spectra were observed upon a gradual increase of the CV. The model compound decamethoxinum allowed us to reveal the extreme situation, in which the mass spectra at a CV below and over approximately 100 V look quite different, in that they contain different product ions of Cat 2R and Cat Á Cl R . While this effect may be much less pronounced for other classes of organic compounds, it should be properly taken into account for the adequate description of fragmentation pathways of bisquaternary ammonium compounds with ESI. Comparison of ESI, FAB-SIMS and MALDI mass spectra of decamethoxinum shows that taking into account CV effects also permits us to gain information on energy deposition into ions generated with the different ionization techniques. 10,[37][38][39][40][41][42] It is believed that the CV effect is due to an in-source collision-induced dissociation (CID) (up-front CID) process. The initially sprayed charged species can undergo collisions with the residual or bath gas on their path between the nozzle and the skimmer, and the change of the ion velocity caused by CV variation affects their kinetic energy and, consequently, their collision energy. 18The possibility of controlling the charge state of the ions, the desolvation process and the degree of fragmentation of the ions by CV variation offers the prospect of many useful applications of this technique, mainly in studies of supramolecular noncovalent complexes. [25][26][27][28][29][30][31][32][33][34][35][36] For example, a method was suggested for evaluating the stability of chemotherapeutic non-intercalating drugs binding to DNA on the basis of monitoring DNA-drug complex decomposition upon CV increase, which correlates with the thermal decomposition of the complex. 25,26 CV adjustment is also of critical importance in probing the structures of surfactant micelles generated under ESI conditions. 30,31 In-source CID is used along with collision-cell tandem mass spectrometric (MS/MS) CID in studies of protein structures. [19][20][21][32][33][34][35][36] Comparison of in-cell CID and in-source CID 32 permits us to obtain more comprehensive information on the molecular structures of analytes. A method, denoted as energydependent ESI mass spectrometry (EDESI-MS), employing CV variation, has been reported for fragmentation studies of metalloorganic compounds.

show abstract

mentioning

confidence: 99%

The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum

Pashynska

Kosevich

Heuvel

et al. 2006

Rapid Comm Mass Spectrometry

View full text Add to dashboard Cite

show abstract

“…Therefore, the formation of metallocorrole positive ions in‐source from divalent metal cations could involve the oxidation of the metal centre. Although atom/ion bombardment induced reductions are well known and are widespread reactions, atom/ion bombardment induced oxidation reactions are much less common 28–31. On the other hand, oxidation reactions in the metal capillary sprayers of mass spectrometers operating in the positive mode are an important step in the overall ionization process, being responsible for charge balance 32, 33…”

Section: Introductionmentioning

confidence: 99%

Study by liquid secondary ion and electrospray mass spectrometry of synthesized and formed‐in‐source metallocorroles

et al. 2006

View full text Add to dashboard Cite

Liquid secondary ion and electrospray mass spectrometry were used to study the complexation in-source of 5,10,15-tris(pentafluorophenyl)corrole with several divalent transition-metal ions. The metallocorrole ions formed in-source were identified by comparing their product ion mass spectra with the spectra of the same ions formed from metallocorroles obtained from classical procedures. Positive metallocorrole ion formation is accompanied by oxidation of the metal centre. Mechanisms were proposed for the oxidation processes, and data from negative-ion spectra reinforced these mechanisms.

show abstract

“…he choice of matrix [1][2][3][4][5][6][7][8][9][10][11][12][13][14] can have a dramatic effect on the appearance of fast atom bombardment (FAB) [15] mass spectra. Important matrix: properties that can affect spectral quality and appearance include viscosity [16][17][18], dielectric constant (which affects ion pairing [19][20][21][22][23][24][25][26][27][28][29][30][31][32]), solvation [33,34], and redox chemistry [10,[35][36][37][38][39][40][41].…”

mentioning

confidence: 99%

m-nitrobenzyl alcohol electrochemistry in fast atom bombardment mass spectrometry

Reynolds

Cook

Burn

et al. 1992

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

The efficacy of m-nitrobenzyl alcohol (NBA) as a solvent (matrix) for fast atom bombardment (FAB) mass spectrometry of a group of pyrazolate-bridged dirhodium A-frame complexes has been assessed. Although NBA is frequently used to mitigate the formation of artifacts in FAB/MS of organometallics and other materials susceptible to bombardment-induced reactions, substantial evidence indicates that such reactions cause the formation of artifacts in the spectra obtained here. Parallel absorption spectroscopic studies have established that NBA is capable of inducing both oxidation and reduction reactions independent of ion bombardment, depending on analyte reduction half-wave potential (E1/2). From the known electrochemistry of the complexes studied, it can be estimated that 1020 mV > E1/2 > 500 mV for the reaction of NBA serving as a reducing agent, while 500 mV > E1/2 > 424 mV for the reduction potential of NBA. However, in the presence of bombardment the former E1/2 must be at least as low as 356 mY, and the latter E1/2 must be at least as high as 1188 mY. The kinetics of redox reactions involving NBA, and therefore their influence on the appearance of FAB mass spectra, will be highly sample-dependent. However, this study illustrates an important potential role for redox reactions when NBA is used as a solvent, especially in the presence of bombardment in FAB/MS. Although analyte reaction products could be identified, substantial efforts aimed at identifying NBA oxidation and reduction products did not yield any definitive results due to the complexity of product mixtures.

show abstract

Desorption chemical ionization, thermospray, and fast atom bombardment mass spectrometry of dihydropyridine .dblharw. pyridinium salt-type redox systems

Cited by 23 publications

References 36 publications

The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum

The effect of cone voltage on electrospray mass spectra of the bisquaternary ammonium salt decamethoxinum

Study by liquid secondary ion and electrospray mass spectrometry of synthesized and formed‐in‐source metallocorroles

m-nitrobenzyl alcohol electrochemistry in fast atom bombardment mass spectrometry

Contact Info

Product

Resources

About