Published:Journal of Chromatographic Science,
ISSN 0021-9665Volume
39, Number 9, September 2001, pp. 375-384
Principal
Component Analysis of Polarity and Interaction Parameters in Inverse Gas Chromatography
Károly
Héberger[1], Kasylda Milczewska[2], and Adam Voelkel[2]
[1]Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences
H-1525 Budapest, P.O. Box 17, Hungary and [2]Pozna´n University of Technology,
Institute of Chemical Technology and Engineering, pl. M. Skl/odowskiej-Curie
2, 60-965 Pozna´n, Poland
Inverse gas chromatography is used in the characterization of
aliphatic-aromatic and aromatic ketones, their oximes, and ketone–oxime
or oxime–oxime mixtures. All these organic materials are used as liquid
stationary phases in gas chromatographic columns. A series of polarity and Flory–Huggins
interaction parameters are determined and used to describe the physicochemical
properties of examined materials, metal extractants, and products of their degradation.
Principal component analysis (PCA) is performed on a data matrix consisting
of polarity and interaction parameters for ketones, their oximes, and mixtures.
The calculations are carried out on the correlation matrix. It is found that
seven principal components account for more than 95% of the total variance in
the data, indicating that the polarity (interaction) parameters are not correlating
well. Physical meanings are attributed to the principal components, the most
influential ones being that the first and the second principal components account
for several Flory–Huggins interaction parameters, whereas the fifth is
correlated with criterion “A”. The plots of component loadings show
characteristic groupings of polarity indicators, whereas that of component scores
show several groupings of stationary phases. Cluster analysis provides mainly
the same groupings. PCA allows for the grouping of polarity and solubility parameters
based on the information carried within those parameters. There is no need to
use more than one parameter from each cluster. McReynolds polarity and the partial
molar excess Gibbs free energy of solution per methylene group carry the same
information. The groups of ketones, oximes, and their mixtures can be distinguished
with the use of PCA on the basis of the measured polarity, solubility parameters,
or both.
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