A GC/FT-IR Compound Identification System

Hanna, Alan; Marshall, John; Isenhour, T. L.

doi:10.1093/chromsci/17.8.434

Cited by 47 publications

(19 citation statements)

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“…Background signal, including laser-induced fluorescence from the system optics, was removed by subtracing a separatelyacquired background spectrum. The Raman shift axis was calibrated with polystyrene to correct for spectral instabilities in the laser diode and fluorescence lineshapes were modeled and removed with an iterative polynomial fitting routine [24,25]. Impulsive noise (e.g., noise due to high-energy cosmic rays) was removed by (1) acquiring multiple frames per acquisition; (2) calculating the median absolute deviation among these frames on a pixel-bypixel basis; and (3) replacing outliers with the median value at that pixel.…”

Section: Data Processingmentioning

confidence: 99%

Co-localized confocal Raman spectroscopy and optical coherence tomography (CRS-OCT) for depth-resolved analyte detection in tissue

Maher

Chuchuen

Henderson

et al. 2015

Biomed. Opt. Express

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Abstract:We report the development of a combined confocal Raman spectroscopy (CRS) and optical coherence tomography (OCT) instrument (CRS-OCT) capable of measuring analytes in targeted biological tissues with sub-100-micron spatial resolution. The OCT subsystem was used to measure depth-resolved tissue morphology and guide the acquisition of chemically-specific Raman spectra. To demonstrate its utility, the instrument was used to accurately measure depth-resolved, physiologicallyrelevant concentrations of Tenofovir, a microbicide drug used to prevent the sexual transmission of HIV, in ex vivo tissue samples.

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Section: Data Processingmentioning

confidence: 99%

Co-localized confocal Raman spectroscopy and optical coherence tomography (CRS-OCT) for depth-resolved analyte detection in tissue

Maher

Chuchuen

Henderson

et al. 2015

Biomed. Opt. Express

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“…This makes it possible to reconstruct a chromatogram in real time by a vector technique called the Gram-Schmidt method (Malissa, 1983). After the acquisition is finished, the spectra of each GC peak can be normalized and searched by comparison with an IR spectra library (Hanna et al, 1979;Seelemann, 1982). In the earlier days of this technique, there were many discussions and studies about its sensitivity followed by the possible overloading of the columns when a capillary GC is used.…”

Section: Gas Chromatography-fourier Transform Infrared Spectroscopy (mentioning

confidence: 99%

Hyphenated Techniques in Gas Chromatography

Guo¹,

Lankmayr²

2012

Advanced Gas Chromatography - Progress in Agricultural, Biomedical and Industrial Applications

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“…We used a 100-point segment displaced 60 points from the light burst as this region has been determined optimal for our GC/FTIR instrument. The notation will change as follows: Ism@) = I (14) Iredd) = R (15) The mechanics of this simplification and can be found in the Appendix.…”

Section: A($ = E(o)bcmentioning

confidence: 99%

Quantitative gas chromatography/Fourier transform infrared spectrometry with integrated gram-Schmidt reconstruction intensities

Sparks¹,

Lam²,

Isenhour³

1982

Anal. Chem.

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An Interferogram-based callbratlon curve approach to quantltatlve GCIFTIR using Integrated Gram-Schmidt reconstructlon lntensltles Is presented. The expected quantltatlve response Is derived from theory and supported wlth emplrlcal evidence. Accurate on-the-fly quantltatlon Is demonstrated over a concentration range correspondlng to absolute analyte amounts ranging from 1 pg to greater than 100 pg using pentyl propionate as the analyte.The combination of the separation ability of a gas chromatograph with the identification ability of an infrared spectrometer (GCIR) became practical with the introduction of rapid scanning Fourier transform infrared (FTIR) spectrometers in the 1960s. Subsequent development in the early 1970s has made GC/FTIR useful for a variety of qualitative applications which have been reviewed by Erikson ( I ) . The quantitative capabilities of the technique, however, have been little explored to date.The myriad difficulties associated with any attempt at absolute quantitation using FTIR have been outlined by Hirschfeld (2). Anderson and Julian have proposed using library absorptivity values for rough (=t25%) absolute quantitation of GC/FTIR data (3). While the dramatic improvement in spectral accuracy obtainable with Fourier transform instruments offers hope for the future development of accurate absolute quantitative methodology, researchers are currently limited to a calibration curve approach for handling the effects of large interlaboratory variance in instrumental and mathematical operating parameters. Erikson used a calibration curve approach for quantifying carbonyl sulfide and ammonia concentrations in coal gas, using one analytical wavelength for each component (4). Mamantov and co-workers also used a single wavelength calibration curve approach for quantifying matrix isolation GC/FTIR data (5). Greater sensitivity in quantitative trace gas analysis was demonstrated by Haaland, who used a least-squares approach employing the entire IR spectral range (6).The quantitative on-the-fly detection of GC/FTIR eluents involves several additional considerations. Upon exit from the chromatograph, absorbing species are in the vapor state diluted by a substantial volume of inert carrier gas. The variance of absorptivity with concentration due to intermolecular bonding effects (7) is thus minimized, extending the linear range of absorbance vs. concentration profiles. However, several complicating factors arise at the interface between the chromatograph and the spectrometer. The effective pathlength of the light pipe interface as it relates to factors such as the temperature and reflectivity of the gold surface in the light pipe must be determined to allow absolute quantitation using measured absorptivities (3). Additionally, the light pipe Foxboro Analytical, 140 Water St., P.O.B. 5449, Norwalk, CT 06856.can hardly be considered a zero dead volume chromatographic detector. The quantitative GCIR response must therefore be corrected for the effects of flow rate and light pipe volume. On the other han...

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A GC/FT-IR Compound Identification System

Cited by 47 publications

References 0 publications

Co-localized confocal Raman spectroscopy and optical coherence tomography (CRS-OCT) for depth-resolved analyte detection in tissue

Co-localized confocal Raman spectroscopy and optical coherence tomography (CRS-OCT) for depth-resolved analyte detection in tissue

Hyphenated Techniques in Gas Chromatography

Quantitative gas chromatography/Fourier transform infrared spectrometry with integrated gram-Schmidt reconstruction intensities

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