Atmospheric Pressure Laser Ionization. An Analytical Technique for Highly Selective Detection of Ultralow Concentrations in the Gas Phase

Schmidt, Steven J.; Appel, M. F.; Garnica, R. M.; Schindler, R. N.; Benter, Thorsten

doi:10.1021/ac9901900

Cited by 32 publications

(45 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This sensitivity enhancement has also been verified experimentally [2,3]. When coupled to the Bruker TOF1, the MPLI source fosters detection of NO down to sub-pptV levels.…”

Section: Sensitivitymentioning

confidence: 60%

“…The pulsing experiment was performed while investigating the two-color NO REMPI spectroscopy [2] and required two relatively unfocused laser beams. Further experimentation with NO 2 through the following stepwise optical double resonant two-color excitation [3],…”

Section: Characterization Of the Ion Sourcementioning

confidence: 99%

“…Utilizing a novel pulsed valve capable of time-resolved sampling at atmospheric pressure coupled to a variety of time-of-flight (TOF) mass spectrometers, several atmospherically relevant trace gases have been selectively and sensitively detected in the laboratory. This technique was recently introduced by our group as "Atmospheric Pressure Laser Ionization Mass Spectrometry" (APLI-MS) [2,3].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Development of medium pressure laser ionization, MPLI. Description of the MPLI ion source

Appel

Short

Benter

2004

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

A novel pulsed valve/ion source combination capable of time-resolved sampling from atmospheric pressure has been developed for use with laser ionization time of flight mass spectrometry. The source allows ionization extremely close to the nozzle of the pulsed valve, enabling ultra-sensitive detection of a number of compounds, e.g., NO, at mixing ratios Ͻ1 pptV. Furthermore, at analyte mixing ratios in the ppbV range, the temporal resolution of the system is in the sub-second regime, allowing time-resolved monitoring of highly dynamic and complex mixtures, e.g., human breath or reacting chemical mixtures in atmospheric smog chamber experiments. Rotational temperatures of ϳ50 K have been observed for analytes seeded in the supersonic jet expansion at a distance of 1 mm downstream of the nozzle orifice. The refinement of the original ion source has drastically reduced the impact of reflected laser light and the resultant electron impact signals previously observed. The general applicability of this technique is demonstrated here by coupling the source to commercially available as well as home-built time-of-flight mass spectrometers. Finally, we discuss the MPLI technique in view of the very recently introduced atmospheric pressure laser ionization (APLI) as well as the traditional jet

show abstract

“…This sensitivity enhancement has also been verified experimentally [2,3]. When coupled to the Bruker TOF1, the MPLI source fosters detection of NO down to sub-pptV levels.…”

Section: Sensitivitymentioning

confidence: 60%

Section: Characterization Of the Ion Sourcementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Development of medium pressure laser ionization, MPLI. Description of the MPLI ion source

Appel

Short

Benter

2004

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…Details on this set-up are given elsewhere [7]. In all experiments, fixed frequency radiation ( ϭ 266 nm, SureLite I Nd:YAG [Continuum, Santa Clara, CA]) was used for non-resonant and near-resonant 2-photon ionization of NO and benzene, respectively.…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…In an effort to create increasingly compact TOF instruments, our research group has focused on novel approaches to instrument design and laser ionization techniques [5][6][7]. With this in mind, we have initiated research that is concerned with the production of "ideal" electrostatic fields.…”

mentioning

confidence: 99%

Conductive carbon filled polymeric electrodes: Novel ion optical elements for time-of-flight mass spectrometers

Appel

Veer

Benter

2002

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

A new technique employing conductive polymeric electrodes for the generation of linear electric fields is proposed and validated. A hollow cylinder comprised of DuPont's Vespel SP-22, a polymer loaded with conductive carbon particles, is used to enhance the performance of a hybrid reflectron compared to a conventional dual stage gridless reflectron composed of discrete metal ring electrodes. Both devices have comparable physical dimensions and nearly identical ion optical properties. Instrumental resolution measurements are used to validate this novel design.

show abstract

Atmospheric‐pressure laser ionization: a novel ionization method for liquid chromatography/mass spectrometry

Constapel

Schellenträger

Schmitz

et al. 2005

Rapid Comm Mass Spectrometry

Self Cite

105

View full text Add to dashboard Cite

We report on the development of a new laser-ionization (LI) source operating at atmospheric pressure (AP) for liquid chromatography/mass spectrometry (LC/MS) applications. APLI is introduced as a powerful addition to existing AP ionization techniques, in particular atmospheric-pressure chemical ionization (APCI), electrospray ionization (ESI), and atmospheric pressure photoionization (APPI). Replacing the one-step VUV approach in APPI with step-wise two-photon ionization strongly enhances the selectivity of the ionization process. Furthermore, the photon flux during an ionization event is drastically increased over that of APPI, leading to very low detection limits. In addition, the APLI mechanism generally operates primarily directly on the analyte. This allows for very efficient ionization even of non-polar compounds such as polycyclic aromatic hydrocarbons (PAHs). The APLI source was characterized with a MicroMass Q-Tof Ultima II analyzer. Both the effluent of an HPLC column containing a number of PAHs (benzo[a]pyrene, fluoranthene, anthracene, fluorene) and samples from direct syringe injection were analyzed with respect to selectivity and sensitivity of the overall system. The liquid phase was vaporized by a conventional APCI inlet (AP probe) with the corona needle removed. Ionization was performed through selective resonance-enhanced multi-photon ionization schemes using a high-repetition-rate fixed-frequency excimer laser operating at 248 nm. Detection limits well within the low-fmol regime are readily obtained for various aromatic hydrocarbons that exhibit long-lived electronic states at the energy level of the first photon. Only molecular ions are generated at the low laser fluxes employed ($1 MW/cm 2 ). The design and performance of the laser-ionization source are presented along with results of the analysis of aromatic hydrocarbons.

show abstract

Atmospheric Pressure Laser Ionization. An Analytical Technique for Highly Selective Detection of Ultralow Concentrations in the Gas Phase

Cited by 32 publications

References 54 publications

Development of medium pressure laser ionization, MPLI. Description of the MPLI ion source

Development of medium pressure laser ionization, MPLI. Description of the MPLI ion source

Conductive carbon filled polymeric electrodes: Novel ion optical elements for time-of-flight mass spectrometers

Atmospheric‐pressure laser ionization: a novel ionization method for liquid chromatography/mass spectrometry

Contact Info

Product

Resources

About