Tetrachlorodibenzo-p-Dioxin Isomer Differentiation by Capillary Gas Chromatography Fourier Transform-Infrared Spectroscopy

1987 ◽  
Vol 41 (5) ◽  
pp. 809-820 ◽  
Author(s):  
James Grainger ◽  
Leslie T. Gelbaum
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Vapor Phase ◽  
Valence Bond ◽  
Fourier Transform Infrared ◽  
Molecular Geometry ◽  
Ether Linkage ◽  
Relative Electron ◽  
Ft Ir ◽  
Infrared Frequencies

Reference infrared vapor-phase spectra of the 22 tetrachlorodibenzo-dioxin (TCDD) isomers were recorded at low microgram concentrations. These reference spectra of synthetic mixture components separated chromatographically or by spectral subtraction exhibit distinct infrared spectra for each isomer. The infrared frequencies are delineated in correlation tables and are interpreted in terms of substitution patterns which determine the strength of the ether linkage. Absorbance values in the 1330–1280 cm−1 (C-O-C asymmetric stretch) region correlate with specific substitution patterns and molecular geometry. Relative electron-withdrawing capacities for chlorinated aromatic rings in TCDD isomers were estimated on the basis of relative capacities determined for model compounds. Qualitative correlations were established between electron-withdrawing capacities and the effects of resonance and field interactions on the ether linkage absorption frequencies of individual TCDD isomers. Gas chromatography Fourier transform infrared (GC/FT-IR) isomer assignments are generally consistent with those obtained by proton Fourier transform nuclear magnetic resonance (1H FT/NMR) and flame ionization gas chromatography (GC/FID). A chromatographically independent method of assigning TCDD isomer structures on the basis of ether linkage asymmetric stretching frequencies was established by utilization of valence-bond approximations. GC/FT-IR assignments for several TCDD isomers differ from isomer assignments in previously published results. A user-generated, vapor-phase reference library, containing individual TCDD spectra and spectra of isomer pairs that are incompletely resolved on chromatographic columns, correctly identified each isomer in variety of mixtures by means of a software algorithm.

Hexachlorodibenzo-p-Dioxin Isomer Differentiation by Capillary Gas Chromatography Fourier Transform Infrared Spectroscopy

1990 ◽  
Vol 44 (1) ◽  
pp. 41-46 ◽  
Author(s):  
James Grainger ◽  
V. Vikram Reddy ◽  
Donald G. Patterson
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Vapor Phase ◽  
Valence Bond ◽  
Mixture Component ◽  
Ether Linkage ◽  
Stretching Vibration ◽  
Isomer Differentiation

Vapor-phase infrared spectra of the 10 hexachlorodibenzo- p-dioxin isomers were recorded at low microgram concentrations. A unique infrared spectrum was observed for each chromatographically separated or spectrally subtracted mixture component. The structures for individual isomers in each isomer pair were assigned by qualitative valence bond evaluations and empirically derived quantitative estimations of ether linkage asymmetric stretching frequencies and by correlations with characteristic aromatic skeletal stretching vibration patterns.

Examination of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part III

1987 ◽  
Vol 41 (7) ◽  
pp. 1163-1169 ◽  
Author(s):  
W. M. Coleman ◽  
Bert M. Gordon
Keyword(s):  
Fourier Transform ◽  
Solid State ◽  
Vapor Phase ◽  
Infrared Spectra ◽  
Steric Hindrance ◽  
Fourier Transform Infrared ◽  
Fourier Transform Infrared Spectra ◽  
The Matrix ◽  
Ft Ir ◽  
Carbonyl Absorption

Matrix-isolated (MI) Fourier transform infrared spectra (FT-IR) have been collected on a series of esters and ketones. The values for the carbonyl absorption are intermediate between the values for vapor-phase (VP) and solid-state (SS) phases. The spectra reveal a splitting or broadening of the carbonyl absorption in the majority of cases for both compound types. The splitting, on the order of 5 to 10 cm−1, does not appear to be a function of concentration at ≤20 ng on the cryogenic disk. The splitting is also not unequivocally due to steric hindrance about the carbonyl group. Compounds with liner as well as branched substituents display spectra having split carbonyl absorptions. Isolation of molecules within multiple types of matrix sites is advanced as the predominant cause of the splitting phenomenon. Implications and consequences of the observed splitting are discussed.

scholarly journals Desulfurisasi Katalitik Tiofen Menggunakan Katalis CoMo/USY dalam Reaktor Batch

2018 ◽  
Vol 14 (1) ◽  
pp. 119
Author(s):  
Khoirina Dwi Nugrahaningtyas ◽  
Nanda Pratiwi ◽  
Eddy Heraldy
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Mass Spectra ◽  
Fourier Transform Infrared ◽  
Activity Test ◽  
Ft Ir ◽  
Increasing Temperature ◽  
Desulfurization Activity

<p>Telah dilakukan uji aktivitas katalis CoMo/USY pada reaksi desulfurisasi tiofen. Reaksi dilakukan pada reaktor sistem batch dengan tekanan gas N<sub>2</sub> sebesar 1 bar gas N<sub>2</sub> dan waktu reaksi selama 1 jam. Penelitian ini bertujuan untuk mengetahui pengaruh variasi temperatur dan variasi karakter katalis pada reaksi desulfurisasi tiofen. Product desulfurisasi dianalisis dengan <em>Gas Chromatography - Mass Spectra </em>(GC-MS). Karakter kestabilan struktur katalis dilihat dengan analisis menggunakan instrumen <em>Fourier Transform Infrared Spectroscopy</em> (FT-IR). Hasil analisis terhadap uji aktivitas desulfurisasi menunjukkan bahwa pada rentang temperatur 200-300°C, rendemen bertambah dengan meningkatnya temperatur. Pada penelitian telah berhasil menghidrogenasi tiofen, tetapi belum bisa menghilangkan kandungan sulfurnya. Adapun efek karakter katalis terhadap aktivitas katalitiknya menunjukkan bahwa karakter katalis yang paling dominan adalah sifat keasaman. Katalis dengan keasaman tertinggi, yaitu katalis CoMo/USY, memiliki aktivitas tertinggi dengan rendemen produk sebesar 2,88%. Hasil analisis FT-IR terhadap katalis bekas menunjukkan bahwa struktur cukup stabil dan tidak ada pengotor yang terikat pada katalis.</p><p><strong>Catalytic Desulfurization of Thiophene </strong><strong>using</strong><strong> CoMo/USY Catalyst </strong><strong>in</strong><strong> Batch Reactor</strong>. CoMo/USY catalyst activity has been tested for thiophene desulfurization reaction. The reaction was carried out in batch system reactor with N<sub>2</sub> gas pressure of 1 bar and reaction time for 1 hour. This study aims to determine the effect of temperature variation and catalyst character variation in thiophene desulfurization reaction. The desulfurization products were analyzed by <em>Gas Chromatography - Mass Spectra </em>(GC-MS). The characters of structure catalyst were analyzed by <em>Fourier Transform Infrared Spectroscopy</em> (FT-IR). The results of the analysis of the desulfurization activity test showed that in the temperature range 200-300 °C, the yield raised with increasing temperature. The analysis results of the desulfurization activity test showed that in the temperature range of 200-300°C, the yield raised with increasing temperature. The study has successfully hydrogenated thiophene, but has not been able to eliminate the sulfur content. The effect of the catalysts character on its catalytic activity shows that the most dominant character of the catalysts was its acidity. The highest acidity catalyst, CoMo/USY catalyst, has highest activity with the product yield of 2,88%. The result of the FTIR analysis on the used catalyst show that the structure was stable and no impurities were attached the catalyst.</p>

Fourier Transform Infrared Spectrometer Coupled with Electrothermal Atomizer for High-Temperature Vapor-Phase Investigations

1984 ◽  
Vol 38 (5) ◽  
pp. 715-720 ◽  
Author(s):  
Paolo Tittarelli ◽  
Tiziana Zerlia ◽  
Giovanna Ferrari
Keyword(s):  
Fourier Transform ◽  
Vapor Phase ◽  
Fourier Transform Infrared ◽  
Infrared Spectrometry ◽  
Pyrolysis Products ◽  
Electrothermal Atomizer ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Phase Behaviors

An electrothermal atomizer is employed to vaporize solid samples of pigments at temperatures ranging from 150°C to 1000°C The evolution of vapors is followed by Fourier transform infrared spectrometry (FT-IR) The atomizer acts at the same time as vapor supplier and vapor holder This coupling allows the investigation in situ of vaporization or pyrolysis phenomena avoiding the use of heated transfer pipes The pigments examined in this study show various vapor-phase behaviors Some pigments vaporize without appreciable decomposition at temperatures from 400°C to 950°C, while other pigments investigated decompose during the heating and originate pyrolysis products whose evolution is monitored continuously by the FT-IR spectrometer

Quantitative Analysis of Sulfur Dioxide with Passive Fourier Transform Infrared Remote Sensing Interferogram Data

2000 ◽  
Vol 54 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Mutua J. Mattu ◽  
Gary W. Small ◽  
Roger J. Combs ◽  
Robert B. Knapp ◽  
Robert T. Kroutil
Keyword(s):  
Remote Sensing ◽  
Fourier Transform ◽  
Sulfur Dioxide ◽  
Temperature Variation ◽  
Multivariate Calibration ◽  
Fourier Transform Infrared ◽  
Calibration Models ◽  
Ft Ir ◽  
Infrared Frequencies ◽  
The Impact

Multivariate calibration models are developed for the determination of sulfur dioxide (SO2) by passive Fourier transform infrared (FT-IR) remote sensing measurements. In a series of experiments designed to simulate the measurement of SO2 from industrial stack emissions, low-angle sky backgrounds are viewed through the windows of a heated flow-through gas cell. With this apparatus, infrared emission from the hot SO2 is measured against the cold background of the sky. The FT-IR interferogram data collected are analyzed directly in the construction of the calibration models. Bandpass digital filters are applied to the interferograms to isolate the modulated infrared frequencies corresponding to either the asymmetric or symmetric S–O stretching vibrations at 1361 and 1151 cm−1, respectively. Quantitative calibration models are constructed by submitting short segments of the filtered interferograms to partial least-squares regression analysis. The experimental design allows the impact of variation in the temperature of the SO2 to be evaluated for its effect on the calibration models. Three data sets are constructed consisting of data with increasing temperature variation. When the temperature variation in the data is less than 30 °C, the calibration models are able to achieve a cross-validation standard error of prediction (CV-SEP) of approximately 27 ppm-m across the 185 to 727 ppm-m range of density-corrected, path-averaged concentration. These calibration models are applied to an interferogram segment of only 250 points, and do not require any separate measurement of the infrared background. A comparison of the results from the interferogram-based analyses with those obtained in an analysis of single-beam spectral data reveals similar performances for the models computed with both types of data.

Pentachlorodibenzo-p-dioxin Isomer Differentiation by Capillary Gas Chromatography Fourier Transform Infrared Spectroscopy

1988 ◽  
Vol 42 (5) ◽  
pp. 800-806 ◽  
Author(s):  
James Grainger ◽  
V. Vikram Reddy ◽  
Donald G. Patterson
Keyword(s):  
Gas Chromatography ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Valence Bond ◽  
Mixture Component ◽  
Ether Linkage ◽  
Nonbonded Interactions ◽  
Isomer Differentiation ◽  
Phase Spectra

Reference infrared vapor-phase spectra of the 14 pentachlorodibenzo-p-dioxin (PnCDD) isomers were recorded at low microgram concentrations. A unique infrared spectrum corresponding to each chromatographically separated or spectrally subtracted mixture component was observed. The structures for individual isomers in each isomer pair were assigned by qualitative valence-bond evaluations and empirically derived quantitative estimations of ether linkage asymmetric stretching frequencies [ vcoc(asym)] Correlations between calculated ether linkage (C-O-C) bond angles and vcoc(asym) indicate the existence of buttressed 1,6 and 1,9 nonbonded interactions not observed in tetrachlorodibenzo- p-dioxin (TCDD) isomers.

Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) for Rapid Determination of Microbial Cell Lipid Content: Correlation with Gas Chromatography-Mass Spectrometry (GC-MS)

2017 ◽  
Vol 71 (10) ◽  
pp. 2344-2352 ◽  
Author(s):  
Aaron Millan-Oropeza ◽  
Rolando Rebois ◽  
Michelle David ◽  
Fathi Moussa ◽  
Alexandre Dazzi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Fourier Transform ◽  
Lipid Content ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Transmission Mode ◽  
Gas Chromatography Mass Spectrometry ◽  
Ft Ir

There is a growing interest worldwide for the production of renewable oil without mobilizing agriculture lands; fast and reliable methods are needed to identify highly oleaginous microorganisms of potential industrial interest. The aim of this study was to demonstrate the relevance of attenuated total reflection (ATR) spectroscopy to achieve this goal. To do so, the total lipid content of lyophilized samples of five Streptomyces strains with varying lipid content was assessed with two classical quantitative but time-consuming methods, gas chromatography–mass spectrometry (GC-MS) and ATR Fourier transform infrared (ATR FT-IR) spectroscopy in transmission mode with KBr pellets and the fast ATR method, often questioned for its lack of reliability. A linear correlation between these three methods was demonstrated allowing the establishment of equations to convert ATR values expressed as CO/amide I ratio, into micrograms of lipid per milligram of biomass. The ATR method proved to be as reliable and quantitative as the classical GC-MS and FT-IR in transmission mode methods but faster and more reproducible than the latter since it involves far less manipulation for sample preparation than the two others. Attenuated total reflection could be regarded as an efficient fast screening method to identify natural or genetically modified oleaginous microorganisms by the scientific community working in the field of bio-lipids.

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