Dense gas chromatograph/mass spectrometer interface

Randall, L. G.; Wahrhaftig, Austin L.

doi:10.1021/ac50034a035

Cited by 78 publications

(33 citation statements)

References 11 publications

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“…The physical and chemical properties of supercritical fluids, such as carbon dioxide, can be used to bridge the gap between these two techniques, allowing high-resolution chromatographic separations of less volatile and thermally labile compounds with relatively short analysis times. ' The coupling of SFC with mass spectrometry (MS) was first demonstrated in 1978, 3 and since then many reports of SFC/MS have been made, including applications to the analysis of polycyclic aromatic hydrocarbons (PAH).4-7 The majority of these early reports of + NRCC #31956. 'Under contract from Sciex, 55 Glen Cameron Road, Thornhill, Ontario, L3T 1P2, Canada.…”

mentioning

confidence: 99%

Analysis of polycyclic aromatic compounds by supercritical fluid charomatography/mass spectrometry using atmospheric‐pressure chemical ionization

Anacleto

Ramaley

Boyd

et al. 1991

Rapid Comm Mass Spectrometry

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The development of microbore packed-column supercritical fluid chromatography/atmospheric pressure chemical ionization mass spectrometry (SFCIAPCI-MS) for the analysis of polycyclic aromatic compounds (PAC) is described. The SFC system was coupled to the mass spectrometer using an improved interface designed to accommodate commercially available fused silica restrictors. The atmospheric pressure chemical ionization characteristics of PAC are discussed and the use of chemical ionization reagents to modify the type of spectra obtained is described. With selected-ion monitoring techniques the interface provided detection limits in the low picogram range for individual PAC standards. Using a photoionization detector for the off-line optimization of chromatographic conditions, SFC/APCI-MS was applied to the analysis of complex mixtures of PAC in coal tar and tar sand oil extracts. Tandem mass spectrometry was used to provide structural information.The analysis of polycyclic aromatic compounds (PAC) in new liquid fuels is of considerable importance due to concern over the mutagenicity and carcinogenicity of many of these compounds.' The difficulties associated with the characterization of these fuels are due primarily to the complexity of the matrices involved and the overwhelming number of isomers of the highermolecular-weight PAC present. Methods of analysis that offer good chromatographic resolving power coupled with selective and sensitive detection are therefore required.Although gas chromatography (GC) possesses unparalleled resolving power and can be coupled easily with mass spectrometry (GUMS), its applicability is restricted by the limited volatility of higher-molecularweight PAC. Less volatile compounds can be anlaysed by high-performance liquid chromatography (HPLC), but excessively long analysis times are required for efficient separations. The physical and chemical properties of supercritical fluids, such as carbon dioxide, can be used to bridge the gap between these two techniques, allowing high-resolution chromatographic separations of less volatile and thermally labile compounds with relatively short analysis times. ' The coupling of SFC with mass spectrometry (MS) was first demonstrated in 1978,3 and since then many reports of SFC/MS have been made, including applications to the analysis of polycyclic aromatic hydrocarbons (PAH).4-7 The majority of these early reports of + NRCC #31956. 'Under contract from Sciex,

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mentioning

confidence: 99%

Analysis of polycyclic aromatic compounds by supercritical fluid charomatography/mass spectrometry using atmospheric‐pressure chemical ionization

Anacleto

Ramaley

Boyd

et al. 1991

Rapid Comm Mass Spectrometry

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“…We are aware of previous attempts to produce short, high current density pulses of electrons by laser beam interaction with metals [10,11]. In these cases, electron beams in the microsecond timescale could only be obtained because the thermionic electron emission dominates when photon energies are in volved that lie below the work function of the metal.…”

mentioning

confidence: 99%

Notizen: Fast Pulsed Laser Induced Electron Generation for Electron Impact Mass Spectrometry

Rohwer

Beavis

Köster

et al. 1988

Zeitschrift Für Naturforschung A

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A new ultra fast electron impact (EI) ion source is pre sented that produces a very short, high intensity electron beam, allowing medium resolution mass spectra to be re corded without pulsing the ion accelerating voltages in a time-of-flight mass spectrometer (TOF-MS). The ion source requires minimum modification of any TOF-MS equipped with an electrostatic ion reflector and UV-laser. El-spectra are presented for comparison with literature spectra.The time-of-flight mass spectrometer with laser induced multiphoton ionization (MUPI-TOF-MS) used in our laboratory has already been described [1]. The unique features of this instrument include high mass range, ionization in a collisionless environment (no adduct ions, no influence of matrix on fragmenta tion patterns), selective and very efficient ionization by resonant MUPI, the possibility to change the frag mentation from soft to hard by merely adjusting the ionizing photon density and simultaneous collection of all ions.A desirable feature for the instrument would be a simple electron impact (El)-source with sufficient sen sitivity to monitor neutral molecules introduced into the supersonic jet [2]. Electron impact ionization com plements the selective resonant MUPI, in the sense that all compounds are ionized, ionization efficiencies do not vary greatly from one compound to the next, large libraries of EI spectra are readily available and unknown spectra can be interpreted by well estab lished rules.These features are of utmost importance to the qualitative and quantitative analysis of unknown mix tures with coupled chromatography-MS techniques. The belief that our instrument could provide the extraordinary sensitivity required for the new genera tion of high resolution chromatographic techniques (capillary LC [3,4], capillary zone electrophoresis [5] and micellar electrokinetic capillary chromatography [6]) gave the final impetus for the design of this novel combined MUPI/EI-source.The ion source is shown schematically in Figure 1. The modification required for EI-ionization consists merely of a 0.25 mm Ta wire held in place between the repeller and the first extraction lens of the ion source at an electric potential intermediate to that of the two mentioned plates. The wire crosses both the molecular beam and the laser beam normally used for MUPI and is perpendicular to both these beams.When photons with an energy higher than the work function of Ta (4.25 eV) hit the wire, a swarm of elec trons instantaneously leave the surface according to the photo-electric effect. These electrons are accelerat ed to the repeller and ionize incoming sample mole cules in the supersonic jet. Molecules closer to the wire at the time of the electron pulse are ionized with less energetic electrons than those nearer the repeller. However, the point of incidence not only defines the electron energy, but also the initial electric potential of the ion formed in the accelerating field. By adjusting the voltage on the ion reflector to selectively reflect ions of limited kinetic energy...

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“…Ordinally the surface temperature of the desolvation Heater (1) and that of the maintenance Heater(2) were kept at ca. 700 and 200° C, respectively.…”

Section: Sfc-msmentioning

confidence: 99%

Development of Directly Coupled Supercritical Fluid Chromatography-Mass Spectrometry with Self-Spouting and Vacuum Nebulizing Assisted Interface

1986

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Supercritical fluid chromatograph (SFC) with a fused silica separation column (0.5 mm I.D.x70 cm) packed with ODS-Q3 (30-50 µm) was directly coupled with a quadrupole mass spectrometer (MS) through a vacuum nebulizing interface originally developed for the combination of high performance liquid chromathograph (HPIC) with MS. Mixtures of hexane and ethanol were used as the mobile phase for SFC at a flow rate of 40 µl/min (50 kg/cm2). The column temperatures were maintained above the critical ones of the mobile phase between 260 and 280°C.Introduction of line filters to remove possible small particles in the SFC effluent and the subtle control of the optimum flow and/or the pressure for the SFC column enabled fairly long term stable operation for this SFC-MS system. Thus developed new system was successfully applied to the analysis of various samples such as styrene oligomers, phthalates, triglycerides, and polyethylene glycol derivatives.

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Dense gas chromatograph/mass spectrometer interface

Cited by 78 publications

References 11 publications

Analysis of polycyclic aromatic compounds by supercritical fluid charomatography/mass spectrometry using atmospheric‐pressure chemical ionization

Analysis of polycyclic aromatic compounds by supercritical fluid charomatography/mass spectrometry using atmospheric‐pressure chemical ionization

Notizen: Fast Pulsed Laser Induced Electron Generation for Electron Impact Mass Spectrometry

Development of Directly Coupled Supercritical Fluid Chromatography-Mass Spectrometry with Self-Spouting and Vacuum Nebulizing Assisted Interface

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