IR-laser photochemistry

Lupo, Donald; Qüack, Martin

doi:10.1021/cr00077a010

Cited by 274 publications

(107 citation statements)

References 87 publications

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“…High-power pulsed IR irradiation was particularly useful for studying multiphoton dissociation of small molecules. Excitation of small molecules usually requires resonant absorption of several IR photons followed by incoherent excitation (Lupo & Quack, 1987). In this case, resonant absorption is the rate-limiting step and presents a ''bottleneck'' for the IR excitation.…”

Section: Multiphoton Dissociationmentioning

confidence: 99%

Activation of large lons in FT‐ICR mass spectrometry

Laskin

Futrell

2004

Mass Spectrometry Reviews

177

146

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The advent of soft ionization techniques, notably electrospray and laser desorption ionization methods, has enabled the extension of mass spectrometric methods to large molecules and molecular complexes. This both greatly extends the applications of mass spectrometry and makes the activation and dissociation of complex ions an integral part of these applications. This review emphasizes the most promising methods for activation and dissociation of complex ions and presents this discussion in the context of general knowledge of reaction kinetics and dynamics largely established for small ions. We then introduce the characteristic differences associated with the higher number of internal degrees of freedom and high density of states associated with molecular complexity. This is reflected primarily in the kinetics of unimolecular dissociation of complex ions, particularly their slow decay and the higher energy content required to induce decomposition-the kinetic shift (KS). The longer trapping time of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) significantly reduces the KS, which presents several advantages over other methods for the investigation of dissociation of complex molecules. After discussing general principles of reaction dynamics related to collisional activation of ions, we describe conventional ways to achieve single-and multiple-collision activation in FT-ICR MS. Sustained off-resonance irradiation (SORI)-the simplest and most robust means of introducing the multiple collision activation process-is discussed in greatest detail. Details of implementation of this technique, required control of experimental parameters, limitations, and examples of very successful application of SORI-CID are described. The advantages of high mass resolving power and the ability to carry out several stages of mass selection and activation intrinsic to FT-ICR MS are demonstrated in several examples. Photodissociation of ions from small molecules can be effected using IR or UV/vis lasers and generally requires tuning lasers to specific wavelengths and/ or utilizing high flux, multiphoton excitation to match energy levels in the ion. Photodissociation of complex ions is much easier to accomplish from the basic physics perspective. The quasi-continuum of vibrational states at room temperature makes it very easy to pump relatively large amounts of energy into complex ions and infrared multiphoton dissociation (IRMPD) is a powerful technique for characterizing large ions, particularly biologically relevant molecules. Since both SORI-CID and IRMPD are slow activation methods they have many common characteristics. They are also distinctly different because SORI-CID is intrinsically selective (only ions that have a cyclotron frequency close to the frequency of the excitation field are excited), whereas IRMPD is not (all ions that reside on the optical path of the laser are excited). There are advantages and disadvantages to each technique and in many applications they complement each other. In contrast wi...

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Section: Multiphoton Dissociationmentioning

confidence: 99%

Activation of large lons in FT‐ICR mass spectrometry

Laskin

Futrell

2004

Mass Spectrometry Reviews

177

146

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“…Recently [29] we have employed a slit-jet supersonic expansion to simplify the spectrum of the ν 1 band around 1085 cm -1 recorded with a tunable diode laser spectrometer, resolving almost completely the K-structure of many P(J) and R(J) multiplets and so improving our earlier results [30]. Here we complete the jet-cooled high-resolution study of the region coming from 2ν 5 and ν 2 + ν 3 for both the bromine isotopologues.…”

Section: Introductionmentioning

confidence: 73%

“…As a consequence, a more reliable and accurate set of spectroscopic parameters has been obtained for 2ν 5 and ν 2 + ν 3 of both the bromine isotopologues. Furthermore, many features belonging to various hot bands have been identified, and the corresponding sets of molecular constants have been determined.…”

Section: Introductionmentioning

confidence: 99%

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Jet-cooled diode laser spectrum and FTIR integrated band intensities of CF₃Br: rovibrational analysis of 2ν₅and ν₂ + ν₃bands near 9 μm and cross-section measurements in the 450–2500 cm⁻¹region

Charmet¹,

Tasinato²,

Stoppa³

et al. 2008

Molecular Physics

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“…[1][2][3][4] Conventionally, LC is frequently coupled with UV-Vis detection for the identification of the separated substances based on their UV-Vis absorption. However, this method is not suitable for analytes that do not absorb in the UV-Vis region.…”

Section: Introductionmentioning

confidence: 99%

Use of CuO Particles as an Interface in LC-FTIR Analysis

et al. 2017

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In this study, the feasibility of using copper oxide (CuO) as an interface for the coupling of liquid chromatography (LC) and Fourier-transform infrared (FTIR) spectroscopy was investigated. CuO exhibits low absorption in the 4000 to 1000 cm -1 FTIR spectral region. In addition, LC-FTIR using CuO as the interface was extended to the analysis of sample mixtures containing benzamide and dioctyl sebacate; both analytes were successfully separated. After complete removal of the mobile phase, benzamide and dioctyl sebacate were successfully identified from the FTIR spectrum. Surprisingly, the interference from adsorbed water or conventionally used LC solvents in the FTIR spectrum was completely eliminated by using CuO particles as the interface in the off-line hyphenation of LC-FTIR. Based on these results, CuO demonstrates potential as an ideal interface for LC-FTIR analysis.

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IR-laser photochemistry

Cited by 274 publications

References 87 publications

Activation of large lons in FT‐ICR mass spectrometry

Activation of large lons in FT‐ICR mass spectrometry

Jet-cooled diode laser spectrum and FTIR integrated band intensities of CF₃Br: rovibrational analysis of 2ν₅and ν₂ + ν₃bands near 9 μm and cross-section measurements in the 450–2500 cm⁻¹region

Use of CuO Particles as an Interface in LC-FTIR Analysis

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IR-laser photochemistry

Cited by 274 publications

References 87 publications

Activation of large lons in FT‐ICR mass spectrometry

Activation of large lons in FT‐ICR mass spectrometry

Jet-cooled diode laser spectrum and FTIR integrated band intensities of CF3Br: rovibrational analysis of 2ν5and ν2 + ν3bands near 9 μm and cross-section measurements in the 450–2500 cm−1region

Use of CuO Particles as an Interface in LC-FTIR Analysis

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Jet-cooled diode laser spectrum and FTIR integrated band intensities of CF₃Br: rovibrational analysis of 2ν₅and ν₂ + ν₃bands near 9 μm and cross-section measurements in the 450–2500 cm⁻¹region