A practical methodology to measure unbiased gas chromatographic retention factor vs. temperature relationships

Baijie Peng, Mei Yi Kuo, Panhia Yang, Joshua T. Hewitt, Paul G. Boswell

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Compound identification continues to be a major challenge. Gas chromatography-mass spectrometry (GC-MS) is a primary tool used for this purpose, but the GC retention information it provides is underutilized because existing retention databases are experimentally restrictive and unreliable. A methodology called "retention projection" has the potential to overcome these limitations, but it requires the retention factor (. k) vs. T relationship of a compound to calculate its retention time. Direct methods of measuring k vs. T relationships from a series of isothermal runs are tedious and time-consuming. Instead, a series of temperature programs can be used to quickly measure the k vs. T relationships, but they are generally not as accurate when measured this way because they are strongly biased by non-ideal behavior of the GC system in each of the runs. In this work, we overcome that problem by using the retention times of 25 n-alkanes to back-calculate the effective temperature profile and hold-up time vs. T profiles produced in each of the six temperature programs. When the profiles were measured this way and taken into account, the k vs. T relationships measured from each of two different GC-MS instruments were nearly as accurate as the ones measured isothermally, showing less than two-fold more error. Furthermore, temperature-programmed retention times calculated in five other laboratories from the new k vs. T relationships had the same distribution of error as when they were calculated from k vs. T relationships measured isothermally. Free software was developed to make the methodology easy to use. The new methodology potentially provides a relatively fast and easy way to measure unbiased k vs. T relationships.

Original languageEnglish (US)
Pages (from-to)207-215
Number of pages9
JournalJournal of Chromatography A
Volume1374
DOIs
StatePublished - Dec 29 2014

Bibliographical note

Publisher Copyright:
© 2014 Elsevier B.V.All rights reserved.

Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.

Keywords

  • Gas chromatography-mass spectrometry
  • Retention database
  • Retention library
  • Retention prediction
  • Retention projection

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