Peer Reviewed: Electron Ionization for LC/MS

Cappiello, Achille; Famiglini, Giorgio; Palma, Pierangela

doi:10.1021/ac0313116

Cited by 25 publications

(22 citation statements)

References 25 publications

(33 reference statements)

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“…Recently, Cappiello et al applied the EI method to LC/MS 11. A stream at a nanoscale flow‐rate is nebulized inside the ion source and proceeds toward a vaporization surface.…”

Section: Introductionmentioning

confidence: 99%

Laser spray: electric field‐assisted matrix‐assisted laser desorption/ionization

Hiraoka

2004

J. Mass Spectrom.

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A new liquid chromatography/mass spectrometry interface, the laser spray, has been developed. Explosive vaporization and mist formation occur when an aqueous solution effusing out from the tip of the stainless-steel capillary is irradiated from the opposite side of the capillary by a 10.6 microm infrared laser. Weak ion signals could be detected when the plume was sampled through the ion sampling orifice. When a high voltage (3-4 kV) was applied to the stainless-steel capillary, strong ion signals appeared. The ion abundances were found to be orders of magnitude greater than those obtained by conventional electrospray ionization in the case of aqueous solutions. The present method is regarded as an electric-field assisted form of matrix-assisted laser desorption/ionization in which the liquid chromatographic solvent (water, etc.) acts as a liquid matrix. Laser spray ionization is expected to become a versatile method for biological mass spectrometry because this method is compatible with the natural solvent, water.

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“…Recently, Cappiello et al applied the EI method to LC/MS 11. A stream at a nanoscale flow‐rate is nebulized inside the ion source and proceeds toward a vaporization surface.…”

Section: Introductionmentioning

confidence: 99%

Laser spray: electric field‐assisted matrix‐assisted laser desorption/ionization

Hiraoka

2004

J. Mass Spectrom.

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“…It is worthwhile to briefly compare our Cold‐EI with SMB approach to the Direct EI approach of Cappiello and co‐workers . In Direct EI, the LC and MS interface is as simple as it gets, and the MS of a GC‐MS can be used with only minor added EI ion‐source and interface modifications.…”

Section: Discussion and Advantagesmentioning

confidence: 99%

“…It is worthwhile to briefly compare our Cold-EI with SMB approach to the Direct EI approach of Cappiello and co-workers. [20][21][22][23][24][25][26][27][28][29][30][31][32] In Direct EI, the LC and MS interface is as simple as it gets, and the MS of a GC-MS can be used with only minor added EI ion-source and interface modifications. However, the LC column flow rate is restricted to below 1 μl/min which necessitates the use of packed capillary Nano LC columns with its resulting lower sample loading ability and loss of concentration sensitivity.…”

Section: Discussion and Advantagesmentioning

confidence: 99%

“…[9] The main EI-LC-MS approach that was used until about a decade ago, particle-beam (PB) LC-MS, [10][11][12][13][14][15] suffers from limited sensitivity, nonlinear response and adverse matrix effects. Cappiello and coworkers demonstrated significant advances in the development of their unique capillary scale PB-LC-MS [16][17][18][19] and in the last 13 years in their advanced direct EI [20][21][22][23][24][25][26][27][28][29][30][31][32] which excels with low LC flow rates while producing library searchable classical EI mass spectra. Moreover, Cappiello and co-workers gave compelling evidence for the lack of matrix related ion suppression or enhancement effects in their direct EI LC-MS [24,30] and demonstrated its strength and usefulness in a few selected interesting applications.…”

Section: Introductionmentioning

confidence: 99%

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Electron ionization LC‐MS with supersonic molecular beams—the new concept, benefits and applications

et al. 2015

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A new type of electron ionization LC-MS with supersonic molecular beams (EI-LC-MS with SMB) is described. This system and its operational methods are based on pneumatic spray formation of the LC liquid flow in a heated spray vaporization chamber, full sample thermal vaporization and subsequent electron ionization of vibrationally cold molecules in supersonic molecular beams. The vaporized sample compounds are transferred into a supersonic nozzle via a flow restrictor capillary. Consequently, while the pneumatic spray is formed and vaporized at above atmospheric pressure the supersonic nozzle backing pressure is about 0.15 Bar for the formation of supersonic molecular beams with vibrationally cold sample molecules without cluster formation with the solvent vapor. The sample compounds are ionized in a fly-though EI ion source as vibrationally cold molecules in the SMB, resulting in 'Cold EI' (EI of vibrationally cold molecules) mass spectra that exhibit the standard EI fragments combined with enhanced molecular ions. We evaluated the EI-LC-MS with SMB system and demonstrated its effectiveness in NIST library sample identification which is complemented with the availability of enhanced molecular ions. The EI-LC-MS with SMB system is characterized by linear response of five orders of magnitude and uniform compound independent response including for non-polar compounds. This feature improves sample quantitation that can be approximated without compound specific calibration. Cold EI, like EI, is free from ion suppression and/or enhancement effects (that plague ESI and/or APCI) which facilitate faster LC separation because full separation is not essential. The absence of ion suppression effects enables the exploration of fast flow injection MS-MS as an alternative to lengthy LC-MS analysis. These features are demonstrated in a few examples, and the analysis of the main ingredients of Cannabis on a few Cannabis flower extracts is demonstrated. Finally, the advantages of EI-LC-MS with SMB are listed and discussed.

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“…27) A stream at a nanoscale flow rate is nebulized inside the ion source and proceeds toward a vaporization surface. During a very short journey, the droplets are converted into solute particles that are vaporized against the hot surface.…”

Section: )mentioning

confidence: 99%

Development of New Ionization Methods for GC/MS and LC/MS Interfaces

Hiraoka

2005

J. Mass Spectrom. Soc. Jpn.

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New ionization methods for GC/MS and LC/MS interface which have been developed in our laboratory will be described. The atmospheric pressure Penning ionization was developed for GC/MS interface. Its sensitivity was found to be as good as that of the electron impact ionization method. The laser spray developed for LC/MS interface, which can be regarded as the electric-field assisted MALDI, gave about one order of magnitude higher ion detection sensitivity than the conventional electrospray. In addition, laser spray can detect ions with di#erent surface activities more non-selectively than electrospray.

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Peer Reviewed: Electron Ionization for LC/MS

Cited by 25 publications

References 25 publications

Laser spray: electric field‐assisted matrix‐assisted laser desorption/ionization

Laser spray: electric field‐assisted matrix‐assisted laser desorption/ionization

Electron ionization LC‐MS with supersonic molecular beams—the new concept, benefits and applications

Development of New Ionization Methods for GC/MS and LC/MS Interfaces

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