Revised solute descriptors for characterizing retention properties of open-tubular columns in gas chromatography and their application to a carborane–siloxane copolymer stationary phase

Poole, Colin F.; Ahmed, Hamid; Kiridena, Waruna; Patchett, Cheryl C.; Koziol, Wladyslaw W.

doi:10.1016/j.chroma.2005.11.062

Cited by 48 publications

(8 citation statements)

References 36 publications

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“…Four groups of three test compounds were selected—one group for each type of interaction except the gas-liquid partition coefficient since the test compounds in each group were selected to cover a range of gas-liquid partition coefficients. The hydrogen bond donors were (listed in order of increasing gas-liquid partition coefficient) phenol, resorcinol, and 1-naphthol; the hydrogen bond acceptors were N , N -dimethylisobutyramide, benzamide, and dextromethorphan; the compounds that interact by π and/or lone pair interactions were ethylbenzene, naphthalene, and anthracene; and the compounds that interact by dipole-dipole and dipole-induced dipole interactions were N , N -diethylacetamide, 4-nitroaniline, and caffeine [25,26]. ( N , N -dimethylisobutyramide and N , N -diethylacetamide are listed in two different groups but they both interact by the same two mechanisms.)…”

Section: Methodsmentioning

confidence: 99%

What experimental factors influence the accuracy of retention projections in gas chromatography–mass spectrometry?

Wilson

Barnes

Boswell

2014

Journal of Chromatography A

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Programmed-temperature gas chromatographic (GC) retention information is difficult to share because it depends on so many experimental factors that vary among laboratories. Though linear retention indexing cannot properly account for experimental differences, retention times can be accurately calculated, or “projected”, from shared isothermal retention vs. temperature (T) relationships, but only if the temperature program and hold-up time vs. T profile produced by a GC is known with great precision. The effort required to measure these profiles were previously impractical, but we recently showed that they can be easily back-calculated from the programmed-temperature retention times of a set of 25 n-alkanes using open-source software at www.retentionprediction.org/gc. In a multi-lab study, the approach was shown to account for both intentional and unintentional differences in the temperature programs, flow rates, and inlet pressures produced by the GCs. Here, we tested 16 other experimental factors and found that only 5 could reduce accuracy in retention projections: injection history, exposure to very high levels of oxygen at high temperature, a very low transfer line temperature, an overloaded column, and a very short column (≤ 15 m). We find that the retention projection methodology acts as a hybrid of conventional retention projection and retention indexing, drawing on the advantages of both; it properly accounts for a wide range of experimental conditions while accommodating the effects of experimental factors not properly taken into account in the calculations. Finally, we developed a four-step protocol to efficiently troubleshoot a GC system after it is found to be yielding inaccurate retention projections.

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Section: Methodsmentioning

confidence: 99%

What experimental factors influence the accuracy of retention projections in gas chromatography–mass spectrometry?

Wilson

Barnes

Boswell

2014

Journal of Chromatography A

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“…ethylbenzene, naphthalene, and anthracene), and compounds that interact by dipole-dipole and dipole-induced dipole interactions (e.g. N,N -diethylacetamide, 4-nitroaniline, and caffeine), and all test compounds vary widely in their gas-liquid partition coefficients [28,29]. All standard compounds were dissolved in ethyl acetate at 100 µM concentration.…”

Section: Methodsmentioning

confidence: 99%

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

Peng

Kuo

Yang

et al. 2014

Journal of Chromatography A

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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 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 2-fold more error. Furthermore, temperature-programmed retention times calculated in five other labs 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.

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“…N , N -diethylacetamide, 4-nitroaniline, and caffeine), and all vary widely in their gas-liquid partition coefficients. 26,27 The test compounds were also selected so that the set of compounds representing each type of interaction elute over a wide range of retention times. They were all dissolved in ethyl acetate at a concentration of 100 μM.…”

Section: Methodsmentioning

confidence: 99%

“Retention Projection” Enables Reliable Use of Shared Gas Chromatographic Retention Data Across Laboratories, Instruments, and Methods

et al. 2013

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Gas chromatography-mass spectrometry (GC-MS) is a primary tool used to identify compounds in complex samples. Both mass spectra and GC retention times are matched to those of standards, but it is often impractical to have standards on hand for every compound of interest, so we must rely on shared databases of MS data and GC retention information. Unfortunately, retention databases (e.g. linear retention index libraries) are experimentally restrictive, notoriously unreliable, and strongly instrument dependent, relegating GC retention information to a minor, often negligible role in compound identification despite its potential power. A new methodology called “retention projection” has great potential to overcome the limitations of shared chromatographic databases. In this work, we tested the reliability of the methodology in five independent laboratories. We found that even when each lab ran nominally the same method, the methodology was 3-fold more accurate than retention indexing because it properly accounted for unintentional differences between the GC-MS systems. When the labs used different methods of their own choosing, retention projections were 4- to 165-fold more accurate. More importantly, the distribution of error in the retention projections was predictable across different methods and labs, thus enabling automatic calculation of retention time tolerance windows. Tolerance windows at 99% confidence were generally narrower than those widely used even when physical standards are on hand to measure their retention. With its high accuracy and reliability, the new retention projection methodology makes GC retention a reliable, precise tool for compound identification, even when standards are not available to the user.

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Revised solute descriptors for characterizing retention properties of open-tubular columns in gas chromatography and their application to a carborane–siloxane copolymer stationary phase

Cited by 48 publications

References 36 publications

What experimental factors influence the accuracy of retention projections in gas chromatography–mass spectrometry?

What experimental factors influence the accuracy of retention projections in gas chromatography–mass spectrometry?

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

“Retention Projection” Enables Reliable Use of Shared Gas Chromatographic Retention Data Across Laboratories, Instruments, and Methods

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