Matrix Isolation Fourier Transform Infrared and Ab Initio Studies of the 193-nm-Induced Photodecomposition of Formamide

1998 ◽  
Vol 102 (33) ◽  
pp. 6643-6650 ◽  
Author(s):  
J. Lundell ◽  
M. Krajewska ◽  
M. Räsänen
Keyword(s):  
Fourier Transform ◽  
Ab Initio ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
193 Nm

Gas Chromatographic/Matrix Isolation/Fourier Transform Infrared Spectra of the Laterally Chlorinated Dibenzo-p-Dioxins and Dibenzofurans

1989 ◽  
Vol 43 (8) ◽  
pp. 1317-1324 ◽  
Author(s):  
Charles J. Wurrey ◽  
Billy J. Fairless ◽  
Harry E. Kimball
Keyword(s):  
Fourier Transform ◽  
Infrared Spectra ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Fourier Transform Infrared Spectra ◽  
Reference Quality ◽  
Ft Ir ◽  
Chlorinated Dioxins ◽  
Chromatographic Matrix ◽  
Ft Ir Spectroscopy

Reference-quality gas chromatographic/matrix isolation/Fourier transform infrared spectra have been recorded for the following fifteen compounds, which collectively are referred to as the “laterally” chlorinated dibenzo- p-dioxins and dibenzofurans: 2,3,7,8-tetrachlorodibenzo- p-dioxin (2,3,7,8-TCDD); 1,2,3,7,8-pentachlorodibenzo- p-dioxin (1,2,3,7,8-PeCDD);l,2,3,4,7,8-hexachlorodibenzo- p-dioxin(1,2,3,4,7,8-HxCDD)>; 1,2,3,6,7,8,-hexachlorodibenzo- p-dioxin(1,2,3,6,7,8-HxCDD); 1,2,3,7,8,9-hexachlorodibenzo- p-dioxin (1,2,3,7,8,9-HxCDD); 1,2,3,4,6,7,8-heptachlorodibenzo- p-dioxin (1,2,3,4,6,7,8-HpCDD); 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF); 1,2,3,7,8-pentachlorodibenzofuran (1,2,3,7,8-PeCDF); 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF); 1,2,3,4,7,8-hexachlorodibenzofuran(1,2,3,4,7,8-HxCDF); 1,2,3,6,7,8-hexachlorodibenzofuran (1,2,3,6,7,8-HxCDF); 1,2,3,7,8,9-hexachlorodibenzofuran (1,2,3,7,8,9-HxCDF); 2,3,4,6,7,8-hexachlorodibenzofuran (2,3,4,6,7,8-HxCDF); 1,2,3,4,6,7,8-heptachlorodibenzofnran (1,2,3,4,6,7,8-HpCDF); and 1,2,3,4,7,8,9-heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF). These spectra are discussed qualitatively and, for the laterally chlorinated dioxins, are compared to previously recorded gas-phase GC/FT-IR spectra. Estimates of the instrumental detection limits for these compounds, using matrix isolation GC/FT-IR spectroscopy, were found to fall in the mid-to-high picogram and low nanogram ranges.

Application of Gas Chromatography/Matrix Isolation/Fourier Transform Infrared Spectroscopy to the Identification of Pyrrolizidine Alkaloids from Comfrey Root (Symphytum officinale L.)

1994 ◽  
Vol 77 (5) ◽  
pp. 1167-1174 ◽  
Author(s):  
Magdi M Mossoba ◽  
Hubert S Lin ◽  
Denis Andrzejewski ◽  
James A Sphon ◽  
Joseph M Betz ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Pyrrolizidine Alkaloids ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Root Extract ◽  
Spectral Bands ◽  
Infrared Spectral ◽  
Fingerprint Region ◽  
Positive Ion

Abstract This paper demonstrates that pyrrolizidine alkaloids (PAs) extracted from comfrey root grown in Washington State (USA) can be identified by gas chromatography/matrix isolation/Fourier transform infrared (GC/MI/FTIR) spectroscopy. Infrared spectral bands observed in the fingerprint region were unique even for closely related structures. The identities of the 4 major components, intermedine, lycopsamine, 7-acetylintermedine, and 7-acetylly-copsamine, were confirmed by comparison with standards. Confirmation was also obtained by using the established techniques of electron ionization and positive ion chemical ionization gas chro-matography/mass spectrometry. The infrared spectra observed for the components of the root extract were consistent with known structures of specific PAs. The identities of the minor components, sym-phytine and its isomers symlandine and/or sym-viridine, in the same extract were not confirmed.

scholarly journals Analysis of IHchothecene Mycotoxins in Contaminated Grains by Gas Chromatography/Matrix Isolation/Fourier Transform Infrared Spectroscopy and Gas Chromatography/Mass Spectrometry

1996 ◽  
Vol 79 (5) ◽  
pp. 1116-1123 ◽  
Author(s):  
Magdi M Mossoba ◽  
Sarah Adams ◽  
John A G Roach ◽  
Mary W Trucksess
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fourier Transform ◽  
Sweet Corn ◽  
Matrix Isolation ◽  
Fourier Transform Infrared ◽  
Epoxide Ring ◽  
Absorption Bands ◽  
Spectral Bands ◽  
Infrared Spectral

Abstract Gas chromatography/matrix isolation/Fourier transform infrared (GC/MI/FTIR) spectroscopy and GC/mass spectrometry (MS) were used to confirm the identities of trimethylsilyl (TMS) derivatives of trichothecene mycotoxins in naturally contaminated grains. Infrared spectral bands observed in the fingerprint region were unique for 10 trichothecene standards. Characteristic absorption bands were observed for the ester (near 1750 cm-1) and ketone (near 1700 cm-1) carbonyl stretching vibrations, the acetate CH3 symmetric bend (1370 cm-1), the epoxide ring (1262 cm-1), the trimethylsilyl CH3 in-plane deformation (1253 cm-1), the ester (O)C-O asymmetric stretching vibration (near 1244 cm-1), and several other bands including intense features due to the TMS function. Infrared bands observed under cryogenic matrix isolation conditions were compared with those found at room temperature in a potassium bromide matrix for 5 of these standards. Identities of deoxynivalenol (DON) from barley and mixed feed, nivalenol from wheat and barley, and DON and fusarenon-x from sweet corn were confirmed by comparison of their infrared spectral bands with those of standards. The identity of DON in the same test samples of sweet corn was confirmed further by GC/MS. GC/MS was also used to quantitate the levels of DON (67-455 ppm) in sweet corn test samples.

Matrix Isolation/Fourier Transform Infrared Spectrometry of Laser-Desorbed Species

1995 ◽  
Vol 49 (7) ◽  
pp. 955-963 ◽  
Author(s):  
B. L. Carr ◽  
R. S. Brown
Keyword(s):  
Fourier Transform ◽  
Carbon Dioxide Laser ◽  
Matrix Isolation ◽  
Sinapinic Acid ◽  
Laser Desorption ◽  
Fourier Transform Infrared ◽  
Maldi Mass Spectrometry ◽  
Infrared Spectrometry ◽  
Coumaric Acid ◽  
Experimental Conditions

Initial results are presented for a novel experimental arrangement which allows the successful study of laser-desorbed neutral species under matrix isolation conditions. In the current work, a pulsed carbon dioxide laser (10.6 μm) is employed for laser desorption. With the combination of a previously described cryogenic trapping technique with coaxial matrix isolation gas (xenon or argon) introduction, laser-desorbed neutrals have been matrix isolated and their Fourier transform infrared spectra recorded. Two different cinnamic acid derivatives ( p-coumaric acid and sinapinic acid) typically employed for matrix-assisted laser ionization (MALDI) mass spectrometry were utilized to demonstrate this new technique. Experimental conditions were determined for optimal matrix isolation of the laser-desorbed species. Two different desorption geometries were examined with respect to their effectiveness for matrix isolation of desorbed neutrals. A covalent dimer of p-coumaric acid produced in an external UV photoreactor and thought to be a possible photoreaction product in UV MALDI was studied by this technique. Thermal degradation of this dimer is shown to occur above threshold irradiance for laser desorption.

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