OSA's Digital Library

Applied Spectroscopy

Applied Spectroscopy

| PUBLISHED BY SAS — AVAILABLE FROM SAS AND OSA

  • Vol. 47, Iss. 10 — Oct. 1, 1993
  • pp: 1612–1619

Improvements in Methods for Spectral Combination of Gas Chromatography/Fourier Transform Infrared Spectroscopic Data

David M. Haaland, Edward V. Thomas, and Dianna S. Blair

Applied Spectroscopy, Vol. 47, Issue 10, pp. 1612-1619 (1993)


View Full Text Article

Acrobat PDF (791 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations
  • Export Citation/Save Click for help

Abstract

Coaddition of spectra in a single-component peak of a gas chromatograph (GC) obtained with a Fourier transform infrared spectrometer is the method generally used to improve the signal-to-noise ratio (S/N) of the spectrum of the eluted analyte. It is commonly thought that coaddition of spectra to a relative intensity level of 40% of the GC peak will lead to the optimal improvement in S/N of the resulting composite spectrum. We have shown that this is not generally the case for either simulated Gaussian-shaped or experimentally obtained asymmetric GC bands. The optimal intensity level for coaddition is found to be a function of the shape of the GC band and the ratio of the number of background to sample scans used in generating the individual IR spectra. We have also introduced the use of classical least-squares (CLS) techniques as a superior method to improve the S/N of the composite analyte spectrum. With the use of CLS methods, spectra included in generating the composite spectrum can be a small fraction of the maximum intensity in the GC peak while still resulting in S/N improvements. The theoretical S/N of the composite spectrum with the use of CLS methods is shown to be always as good as or better than that achieved with the coaddition method. The improvements achieved in S/N when CLS methods are used can be more than a factor of two greater than results for the traditional coaddition method for the cases considered in this paper. Furthermore, it is shown that increasing the number of background to sample scans is a very convenient method to improve the S/N of the composite spectrum obtained by either method. The results presented here for GC/FT-IR are also generally applicable to LC/FT-IR, SFC/FT-IR, and TGA/FT-IR for bands that contain a single analyte.

Citation
David M. Haaland, Edward V. Thomas, and Dianna S. Blair, "Improvements in Methods for Spectral Combination of Gas Chromatography/Fourier Transform Infrared Spectroscopic Data," Appl. Spectrosc. 47, 1612-1619 (1993)
http://www.opticsinfobase.org/as/abstract.cfm?URI=as-47-10-1612


Sort:  Journal  |  Reset

References

References are not available for this paper.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited