Gas chromatography - infrared

Figure 15.11 (a) Total ion clnomatogram of a Grob test mixture obtained on an Rtx-1701 column, and (b) re-injection of the entire clnomatogram on to an Rtx-5 column. Peak identification is as follows a, 2,3-butanediol b, decane c, undecane d, 1-octanol e, nonanal f, 2,6-dimethylphenol g, 2-ethylhexanoic acid h, 2,6-dimethylaniline i, decanoic acid methyl ester ], dicyclohexylamine k, undecanoic acid, methyl ester 1, dodecanoic acid, methyl ester. Adapted from Journal of High Resolution Chromatography, 21, M. J. Tomlinson and C. L. Wilkins, Evaluation of a semi-automated multidimensional gas chromatography-infrared-mass specti ometry system for initant analysis , pp. 347-354, 1998, with permission from Wiley-VCH. 

K. A. Kr Ock, N. Ragunathan, C. Klawun, T. Sasaki and C. L. Wilkins, Multidimensional gas chromatography-infrared spectrometry-mass spectr ometry . Analyst 119 483-489(1994). 

The identity and purity of the product were determined by gas chromatography, infrared spectroscopy, and proton magnetic resonance spectroscopy by both the submitters and the checkers. 

Concrete applications of micro reactors for chemical analysis, albeit so far not a core application, have been described [5]. Among other uses in chemical analysis, micro devices for gas chromatography, infrared spectroscopy, and photoacoustic detection are mentioned. 

Chemical Testing. Adequate instrumentation for a variety of different test methods should be available. Most stability-indicating chemical assays are performed by high-performance liquid chromatography. Occasionally, gas chromatography, infrared spectrophotometry, or spectrofluorimetry are used. Test... 

Wilkins CL. Directly-Linked Gas Chromatography-Infrared-Mass Spectrometry (GC/ IR/MS). Published Online 15 AUG 2006. 

We discussed the fundamentals of mass spectrometry in Chapter 10 and infrared spectrometry in Chapter 8. The quadrupole mass spectrometer and the Fourier transform infrared spectrometer have been adapted to and used with GC equipment as detectors with great success. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-infrared spectrometry (GC-IR) are very powerful tools for qualitative analysis in GC because not only do they give retention time information, but, due to their inherent speed, they are also able to measure and record the mass spectrum or infrared (IR) spectrum of the individual sample components as they elute from the GC column. It is like taking a photograph of each component as it elutes. See Figure 12.14. Coupled with the computer banks of mass and IR spectra, a component s identity is an easy chore for such a detector. It seems the only real... 

Today, there are many so-called hyphenated methods with IR. These methods include gas chromatography-infrared (GC-IR) where the IR spectra are taken from materials as they are evolved through the column. Related to this are high-performance liquid chromatography-infrared (HPLC-IR), thermogravimetry-infrared (TG-IR), and multispec-tral infrared (MS-IR). 

In this paper, data is cited which demonstrates that diffusional monitoring can be used in circumstances in which pumps and charcoal tubes were previously used. The data cited emphasizes the comparability of diffusional monitoring to charcoal tube and pump. However, it must be noted that the methods are different, and will not in each circumstance yield comparable results. The most conclusive tests will be those which employ a third method (e.g., gas chromatography, infrared analysis) capable of accurately determining the contaminant, or contaminants concentration. 

R. C. Shaler and J. H. Jerpe, Identification and determination of heroin in illicit seizures by combined gas chromatography—infrared spectrophotometry, J. Forens. Sci., 77 668 (1972). 

Ammonia is readily detectable in air in the range of a few parts per million by its characteristic odor and alkaline reaction. Specific indicators, such as Nessler s reagent (Hgk in KOH), can detect ammonia in a concentration of 1 ppm. For the quantitative determination of ammonia in air, synthesis gas and aqueous solutions, these methods can be used74 Acidimetry and Volumetric Analysis By Absorption, Gas Chromatography, Infrared Absorption, Thermal Conductivity Measurement, Electrical Conductivity Measurement, Measurement of Heat of Neutralization, and Density Measurement (for aqueous ammonia). 

ASTM Standard E 1642-94, Standard Practice for General Techniques of Gas Chromatography Infrared (GC/IR) Analysis, American Society for Testing and Material, Philadelphia, February 1995. 

J.A. de Haseth and T.L. Isenhour, Reconstruction of gas chromatograms from interferometric gas chromatography/infrared spectrometry data, Anal. Chem., 49, 1977-1981 (1977). 

Tomlinson, M. J., and Wilkins, C. L. (1989). Evaluation of a semi-automatic multidimensional gas chromatography-infrared-mass spectrometry system for irritant analysis. J. High Resolut. Chromatogr. 21, 347-354. 

T Tnequivocal identification of pesticides that cause stream pollution and thereby affect aquatic organisms requires more evidence than can be provided by gas chromatography. Infrared spectrometry of these toxic substances recovered from the tissues of affected fish can supply firm proof of their identity (I). In using this technique, however, problems are introduced by the large proportions of interfering substances in typical samples. Infrared analysis, furthermore, is less sensitive than gas chromatography. 

Pyrolysis-gas chromatography/infrared spectroscopy (Py-GCIR) A pyrolysis technique in which the volatile pyrolysates are analysed by on-line gas chromatography/infrared spectroscopy. 

Known quantities of reactants are allowed to react for known lengths of time from time to time, samples of the reaction mixture are analyzed quantitatively. You can follow either the disappearance of the reactants or the appearance of the products. Analysis of the reaction might include gas chromatography, infrared or nmr spectroscopy (methyl iodide decrease or ether increase), or reaction with aqueous silver nitrate to precipitate insoluble silver iodide. We shall use still another method—titration of the unreacted base, potassium f-butoxide, with an acid. When using this method aliquots (known fractions) of the reaction mixture are removed and immediately diluted with ice water to stop the reaction. Unreacted f-butoxide ion will react with the water to form hydroxide ion and f-butyl alcohol the base is titrated to a phenolphthalein end point with standard perchloric acid. 

Gas chromatography/infrared spectroscopy analysis was also used under differing operating parameters to aid in compound identification. 

Water can be readily detected by gas chromatography, infrared and H NMR assay. Quantitation can be straightforward if standard data points have been generated that use known amounts of water in the presence of the primary compound to be assayed. The presence of water may be inferred by thermogravimetric assay however, any weight loss may not be specific for water. 

TGA/DSC Delaminations Contamination Dispersion Dynamometer tests SAE J661, FAST, full scale Chemical composition as needed Pyrolytic gas chromatography Infrared analysis X-ray diffraction TGA/DSC Electron microprobe analysis (EMPA) SEM... 

Gas chromatography-infrared spectrometry (GC-IR) combines the separating power of GC with the nondestructive identification capabilities of IR spectometry. 

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