Soft landing of ions as a means of surface modification

Franchetti, V.M.; Solka, B.H.; Baitinger, W. E.; Amy, J. W.; Cooks, R. Graham

doi:10.1016/0020-7381(77)80004-1

Cited by 141 publications

(131 citation statements)

References 6 publications

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“…The instrumentation used for the vacuum-base ion/surface reactions is based on the ion soft landing (SL) technique [36][37][38] in which mass-selected polyatomic ions are deposited intact onto a surface using a mass spectrometer. For surface reactions, the selected ion is given enough energy to react selectively with particular functional groups present at the surface.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Microsolvated Organic Compounds at Ambient Surfaces: Droplet Velocity, Charge State, and Solvent Effects

Badu‐Tawiah

Campbell

Cooks

2012

J. Am. Soc. Mass Spectrom.

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The exposure of charged microdroplets containing organic ions to solid-phase reagents at ambient surfaces results in heterogeneous ion/surface reactions. The electrosprayed droplets were driven pneumatically in ambient air and then electrically directed onto a surface coated with reagent. Using this reactive soft landing approach, acid-catalyzed Girard condensation was achieved at an ambient surface by directing droplets containing Girard T ions onto a dry ketosteroid. The charged droplet/surface reaction was much more efficient than the corresponding bulk solution-phase reaction performed on the same scale. The increase in product yield is ascribed to solvent evaporation, which causes moderate pH values in the starting droplet to reach extreme values and increases reagent concentrations. Comparisons are made with an experiment in which the droplets were pneumatically accelerated onto the ambient surface (reactive desorption electrospray ionization, DESI). The same reaction products were observed but differences in spatial distribution were seen associated with the "splash" of the high velocity DESI droplets. In a third type of experiment, the reactions of charged droplets with vapor phase reagents were examined by allowing electrosprayed droplets containing a reagent to intercept the headspace vapor of an analyte. Deposition onto a collector surface and mass analysis showed that samples in the vapor phase were captured by the electrospray droplets, and that instantaneous derivatization of the captured sample is possible in the open air. The systems examined under this condition included the derivatization of cortisone vapor with Girard T and that of 4-phenylpyridine N-oxide and 2-phenylacetophenone vapors with ethanolamine.

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Section: Introductionmentioning

confidence: 99%

Reactions of Microsolvated Organic Compounds at Ambient Surfaces: Droplet Velocity, Charge State, and Solvent Effects

Badu‐Tawiah

Campbell

Cooks

2012

J. Am. Soc. Mass Spectrom.

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“…Soft-landing, the destruction-free ion beam deposition of molecular ions, 11 has been the topic of numerous studies, 12Ϫ14 most of them aimed at the purification or enrichment of very rare and nonvolatile organic or biological compounds. 15,16 In all of those experiments, it has been demonstrated that it is actually possible to bring nonvolatile compounds from a solution or matrix into the gas phase and to deposit them on a surface, 17,18 where they are present as molecular ion or as neutralized species.…”

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confidence: 99%

Electrospray Ion Beam Deposition: Soft-Landing and Fragmentation of Functional Molecules at Solid Surfaces

et al. 2009

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The ion beam deposition (IBD) of rhodamine dye molecules on solid surfaces in high vacuum is explored in order to characterize the possibility of fabricating molecular coatings or nanostructures from nonvolatile molecules. Molecular ion beams with a well-defined composition are deposited on silicon oxide surfaces with a controlled kinetic energy. Photoluminescence spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) are employed in order to characterize the sample with respect to coverage, homogeneity, and the fraction of intact landed ions (soft-landing ratio). We find that homogeneous rhodamine films of defined composition can be produced at energies of 2؊100 eV. The coverage is found to be proportional to the ion dose. Soft-landing is observed for energies up to 35 eV.

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“…M olecular ion soft-landing, characterized by deposition of intact molecules on surfaces at low kinetic energies [1], has been applied in experiments ranging from studies using chemically inert and structurally organized self-assembled monolayers (SAMs) as substrates for ion storage [2], to studies of ion mobility through ice and vapor deposited films [3,4], to experiments aimed at developing a separation method in a form of preparatory mass spectrometry [5,6]. Simple organic cations [7,8], metal clusters [9], polysaccharides [10], a nucleotide [11], and intact viruses [12][13][14] have all been the targets of examination by ion soft-landing.…”

mentioning

confidence: 99%

Ion soft-landing into liquids: Protein identification, separation, and purification with retention of biological activity

Gologan

Takáts

Alvarez

et al. 2004

J. Am. Soc. Mass Spectrom.

122

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Protein ions, after mass spectrometric separation, can be soft-landed into liquid surfaces with preservation of their native structures. Retention of biological activity is strongly favored in glycerol-based surfaces but not in self-assembled monolayer solid surfaces. Soft-landing efficiency for multiply-charged hexokinase ions was found to be some four times higher for a glycerol/fructose liquid surface than for a fluorinated self-assembled monolayer surface. Soft-landing into liquid surfaces is also shown to allow (1) protein purification, (2) on-surface identification of the soft-landed material using MALDI, and (3) protein identification by in-surface tryptic digestion. Pure lysozyme was successfully isolated from different mixtures including an oxidized, partially decomposed batch of the protein and a partial tryptic digest. Liquid glycerol/carbohydrate mixtures could be used directly to record MALDI spectra on the soft-landed compounds provided they were fortified in advance with traditional MALDI matrices such as p-nitroaniline and ␣-cyano-4-hydroxycinnamic acid. Various proteins were soft-landed and detected on-target using these types of liquid surface. Soft-landing of multiply-charged lysozyme ions onto fluorinated self-assembled monolayer surfaces was found to occur with a limited amount of neutralization, and trapped multiply-charged ions could be desorbed from the surface by laser desorption. Initial data is shown for a new approach to protein identification that combines top-down and bottom-up approaches by utilizing protein ion soft-landing from a protein mixture, followed by tryptic digestion of the landed material and detection of characteristic tryptic fragments by MALDI. , has been applied in experiments ranging from studies using chemically inert and structurally organized self-assembled monolayers (SAMs) as substrates for ion storage [2], to studies of ion mobility through ice and vapor deposited films [3,4], to experiments aimed at developing a separation method in a form of preparatory mass spectrometry [5,6]. Simple organic cations [7,8] [12][13][14] have all been the targets of examination by ion soft-landing. The separation, purification, and storage of chemical species by a completely non-destructive, mass spectrometric approach are the objectives of the studies currently underway in our laboratory.In a preliminary report [5], we described a method which showed the potential for generating biologically active protein chips from protein mixtures by massselective ion soft-landing. After ionization of the mixture by electrospray (ESI), individual protein ions were mass-selected and soft-landed at predetermined locations on the surface. The results showed that the use of mass spectrometry as a separation method in biology provides high selectivity because components with different molecular formulas can be separated and softlanded. However, retention of the biological activity of a protein or other biomolecule in the course of this (or any mass spectrometry experiment) is a much more chall...

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Soft landing of ions as a means of surface modification

Cited by 141 publications

References 6 publications

Reactions of Microsolvated Organic Compounds at Ambient Surfaces: Droplet Velocity, Charge State, and Solvent Effects

Reactions of Microsolvated Organic Compounds at Ambient Surfaces: Droplet Velocity, Charge State, and Solvent Effects

Electrospray Ion Beam Deposition: Soft-Landing and Fragmentation of Functional Molecules at Solid Surfaces

Ion soft-landing into liquids: Protein identification, separation, and purification with retention of biological activity

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