Evidence for the direct desorption of crown ether-metal ion complexes in liquid secondary Ionization Mass Spectrometry

Cunniff, John B.; Vouros, Paul; Kaplan, Dave L.; Fossey, Steve A.

doi:10.1016/1044-0305(94)85005-4

Cited by 6 publications

(3 citation statements)

References 27 publications

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“…23,24 The most common among these clusters are the 1 : 2 "sandwichÏ complexes, in which one metal cation coordinates two molecules of ligand. The abundance of such species is particularly high when the metal cation radius is too large to allow it to Ðt into the cavity of the crown, so that the protruding section of the cation can interact with a second ligand.…”

Section: Investigation Of Solution Equilibria : Fab and Electrospray mentioning

confidence: 99%

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

Vincenti

1995

J. Mass Spectrom.

122

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The study of host-guest chemistry in the gas phase has been pursued systematically only in the last 5 years, after sporadic interest in the 1980s, despite extensive investigation of this chemistry in the condensed phase and the success encountered in several Ðelds of application. Most gas-phase studies have been performed under the controlled conditions that can be achieved inside a mass spectrometer, where solvent e †ects are not present. At this point, the Ðrst evaluation of the achievements and knowledge emerging from these mass spectrometric investigations can be attempted. At the same time, it is possible to evaluate the most promising subjects for future research. This review undertakes these tasks, by presenting (i) applications where mass spectrometry was used to investigate condensed phase equilibria and, more extensively, (ii) experiments where host-guest complexes were formed directly in the gas phase. The latter processes are discussed in detail in relation to the structural and electronic e †ects, the energetic requirements and the dependence on size, rigidity, spatial geometry and functional groups of both hosts and guests. All these e †ects combined are likely to contribute to the strength and multiplicity of the non-covalent bonds that allow the complex to be formed. The macro(poly)cyclic hosts considered include crown ethers, cryptands, cyclodextrins, calixarenes, cryptophanes, cavitands, carcerands and macrolides. The guests are either metal cations or organic molecules and ions.

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Section: Investigation Of Solution Equilibria : Fab and Electrospray mentioning

confidence: 99%

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

Vincenti

1995

J. Mass Spectrom.

122

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“…A number of workers have used mass spectrometry to examine metal ion-peptide complexes that are formed in the condensed phase. These earlier studies were carried out by mixing metal salts with biomolecules in solution and then transferring the sample into the gas phase via ionization methods such as FAB [28][29][30][31][32] or ESI [33][34][35][36] . Studies of peptides cationized with alkali, alkaline, and transition metal ions have provided an understanding of the relationship between fragmentation reactions [29][30][31][32][33][34][35][36][37], the metal ion binding site [32,34], and metal-binding affinities [31,37].…”

Section: Introductionmentioning

confidence: 99%

The reactions of ground state Cu⁺ and Fe⁺ with the 20 common amino acids

Lei

Amster

1996

J. Am. Soc. Mass Spectrom.

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A systematic investigation of the gas-phase reactions of Cu(+) and Fe(+) with the 20 common amino acids is reported. Metal ions are formed by laser ablation of a metal target and are trapped in the analyzer cell of a Fourier transform mass spectrometer. By using quadrupolar excitation to axialize the metal ions, tens of thousands of thermalizing collisions occur prior to their reactions with laser-desorbed amino acid neutral molecules. Amino acids with nonpolar side chains are found to be more reactive toward Cu(+) and Fe(+) than amino acids with polar side chain. Many of the nonpolar amino acids are found to undergo dissociative metal attachment with a neutral loss of 46 u. A (13)C-labeling experiment shows that the carboxyl group is lost during dissociative metal attachment to amino acids. Together these results suggest that these metal ions interact primarily with the carboxyl functional group in these molecules.

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“…Modern mass spectrometry is a fast and versatile method for the detection of labile, nonvolatile macromolecules and supramolecular complexes. Within the past few years, noncovalent interactions in crown ethers and ion carriers have been examined with soft ionization/desorption methods, such as fast atom bombardment (FAB), − matrix assisted laser desorption/ionization (MALDI), and electro s pray ionization (ESI). ,,− Various attempts have been undertaken to quantitatively determine stability constants of ion−ionophore complexes in solution with FAB 5-7,9 and ESI-MS. , In this publication, we present mass spectrometric studies on the cation selectivity of monocyclic ionophores, using the novel technique of laser-induced liquid beam ionization/desorption (LILBID). With this method, we previously examined the dimerization equilibrium of the channel building polypeptide gramicidin D in various alcoholic solutions. , …”

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confidence: 99%

Cation Selectivity of Natural and Synthetic Ionophores Probed with Laser-Induced Liquid Beam Mass Spectrometry

1997

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The novel laser desorption method laser-induced liquid beam ionization/desorption (LILBID) is applied to the mass spectrometric examination of selective ion binding by natural and synthetic ionophores in methanol solutions. The ions are desorbed from a liquid jet with an IR laser pulse and then extracted perpendicularly into a reflectron time-of-flight (RE-TOF) analyzer. LILBID studies on the natural ion carriers valinomycin and monensin A are presented, as well as those on the synthetic crown ethers 18-crown-6, diaza-18-crown-6, and benzo-15-crown-5. No fragment ions are detected, and the measured ion selectivity is in good qualitative agreement with published stability constants of the complexes. The observed specific recognition of silver ions by diaza-18-crown-6 can be rationalized by the principle of hard and soft acids and bases, which predicts stable complexes when the polarizabilities of Lewis acid and base are similar. Weak, noncovalent interactions like those in the sandwich complex between two benzo-15-crown-5 molecules with one potassium ion are detected with LILBID. Their preservation during the process of ion desorption depends on the laser intensity. A comparison with spectra obtained by using electrospray ionization (ESI) and matrix assisted laser desorption/ionization (MALDI) shows that LILBID can potentially become a sensitive tool for the screening of weak but specific molecular interactions.

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Evidence for the direct desorption of crown ether-metal ion complexes in liquid secondary Ionization Mass Spectrometry

Cited by 6 publications

References 27 publications

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

The reactions of ground state Cu⁺ and Fe⁺ with the 20 common amino acids

Cation Selectivity of Natural and Synthetic Ionophores Probed with Laser-Induced Liquid Beam Mass Spectrometry

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Evidence for the direct desorption of crown ether-metal ion complexes in liquid secondary Ionization Mass Spectrometry

Cited by 6 publications

References 27 publications

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

Special feature: Perspective. Host–guest chemistry in the mass spectrometer

The reactions of ground state Cu+ and Fe+ with the 20 common amino acids

Cation Selectivity of Natural and Synthetic Ionophores Probed with Laser-Induced Liquid Beam Mass Spectrometry

Contact Info

Product

Resources

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The reactions of ground state Cu⁺ and Fe⁺ with the 20 common amino acids