Abstract
Increasing the reliability of both GC and GC-MS identification requires appropriate interlaboratory reproducibility of gas chromatographic retention indices (I). Known temperature dependence, I(T), is the main source of non-reproducibility of these parameters. It can be approximated with a simple linear function I(T). However, since mid-1990s-beginning of 2000s some examples of anomalous temperature dependence, I(T), preferably for polar analytes on non-polar stationary phases were revealed independently by different authors. The effect implies the variations in the sign of the temperature coefficients β = dI/dT for selected compounds and, hence, the appearance of the I-extrema (usually, minima).The current work provides evidence that the character of the anomalous I(T[cyrillic]) dependences (ascending, descending, or with extrema) is strongly influenced by the amounts of analytes injected into the chromatographic column, but these anomalies appeared not to be connected directly with the mass overloading of separation systems. The physicochemical model is proposed to describe the observed anomalies of I(T) dependence. This model is based on three previously known principles of chromatography, namely:. i)the dependence of partition coefficients of polar analytes between stationary and gas phases (Kp) can be approximated with the well-known equation (sometimes called as two-parameter Antoine relationship), ln(Kp) = a/T + b;ii)the polarity of the stationary phase of chromatographic column is varied as a result of its dynamic modification with polar analytes;iii)the variations in the retention indices of polar analytes are proportional to the quantity of these polar analyte dissolved in the stationary phase.The superposition of these objectives allows understanding both the unusual temperature dependence of retention indices, and the influence of the amounts of polar analytes injected into GC column on the parameters of this dependence.
| Original language | English |
|---|---|
| Pages (from-to) | 126-134 |
| Number of pages | 9 |
| Journal | Journal of Chromatography A |
| Volume | 1445 |
| DOIs | |
| Publication status | Published - May 6 2016 |
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Keywords
- Gas chromatography
- Non-Polar phases
- Polar analytes
- Retention anomalies
- Retention indices
- Temperature dependence
ASJC Scopus subject areas
- Analytical Chemistry
- Organic Chemistry
- Biochemistry
Cite this
Anomalous temperature dependence of gas chromatographic retention indices of polar compounds on non-polar stationary phases. / Pavlovskii, Alexander A.; Heberger, K.; Zenkevich, Igor G.
In: Journal of Chromatography A, Vol. 1445, 06.05.2016, p. 126-134.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Anomalous temperature dependence of gas chromatographic retention indices of polar compounds on non-polar stationary phases
AU - Pavlovskii, Alexander A.
AU - Heberger, K.
AU - Zenkevich, Igor G.
PY - 2016/5/6
Y1 - 2016/5/6
N2 - Increasing the reliability of both GC and GC-MS identification requires appropriate interlaboratory reproducibility of gas chromatographic retention indices (I). Known temperature dependence, I(T), is the main source of non-reproducibility of these parameters. It can be approximated with a simple linear function I(T). However, since mid-1990s-beginning of 2000s some examples of anomalous temperature dependence, I(T), preferably for polar analytes on non-polar stationary phases were revealed independently by different authors. The effect implies the variations in the sign of the temperature coefficients β = dI/dT for selected compounds and, hence, the appearance of the I-extrema (usually, minima).The current work provides evidence that the character of the anomalous I(T[cyrillic]) dependences (ascending, descending, or with extrema) is strongly influenced by the amounts of analytes injected into the chromatographic column, but these anomalies appeared not to be connected directly with the mass overloading of separation systems. The physicochemical model is proposed to describe the observed anomalies of I(T) dependence. This model is based on three previously known principles of chromatography, namely:. i)the dependence of partition coefficients of polar analytes between stationary and gas phases (Kp) can be approximated with the well-known equation (sometimes called as two-parameter Antoine relationship), ln(Kp) = a/T + b;ii)the polarity of the stationary phase of chromatographic column is varied as a result of its dynamic modification with polar analytes;iii)the variations in the retention indices of polar analytes are proportional to the quantity of these polar analyte dissolved in the stationary phase.The superposition of these objectives allows understanding both the unusual temperature dependence of retention indices, and the influence of the amounts of polar analytes injected into GC column on the parameters of this dependence.
AB - Increasing the reliability of both GC and GC-MS identification requires appropriate interlaboratory reproducibility of gas chromatographic retention indices (I). Known temperature dependence, I(T), is the main source of non-reproducibility of these parameters. It can be approximated with a simple linear function I(T). However, since mid-1990s-beginning of 2000s some examples of anomalous temperature dependence, I(T), preferably for polar analytes on non-polar stationary phases were revealed independently by different authors. The effect implies the variations in the sign of the temperature coefficients β = dI/dT for selected compounds and, hence, the appearance of the I-extrema (usually, minima).The current work provides evidence that the character of the anomalous I(T[cyrillic]) dependences (ascending, descending, or with extrema) is strongly influenced by the amounts of analytes injected into the chromatographic column, but these anomalies appeared not to be connected directly with the mass overloading of separation systems. The physicochemical model is proposed to describe the observed anomalies of I(T) dependence. This model is based on three previously known principles of chromatography, namely:. i)the dependence of partition coefficients of polar analytes between stationary and gas phases (Kp) can be approximated with the well-known equation (sometimes called as two-parameter Antoine relationship), ln(Kp) = a/T + b;ii)the polarity of the stationary phase of chromatographic column is varied as a result of its dynamic modification with polar analytes;iii)the variations in the retention indices of polar analytes are proportional to the quantity of these polar analyte dissolved in the stationary phase.The superposition of these objectives allows understanding both the unusual temperature dependence of retention indices, and the influence of the amounts of polar analytes injected into GC column on the parameters of this dependence.
KW - Gas chromatography
KW - Non-Polar phases
KW - Polar analytes
KW - Retention anomalies
KW - Retention indices
KW - Temperature dependence
UR - http://www.scopus.com/inward/record.url?scp=84979467729&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84979467729&partnerID=8YFLogxK
U2 - 10.1016/j.chroma.2016.03.079
DO - 10.1016/j.chroma.2016.03.079
M3 - Article
C2 - 27062719
AN - SCOPUS:84979467729
VL - 1445
SP - 126
EP - 134
JO - Journal of Chromatography
JF - Journal of Chromatography
SN - 0021-9673
ER -