Page 426 - Multidimensional Chromatography

418 Multidimensional Chromatography

Figure 15.7 Chromatographic separation of chiral hydroxy acids from Pseudomonas aerug-
inosa without (a) and with (b) co-injection of racemic standards. Peak identification is as fol-
lows: 1, 3-hydroxy decanoic acid, methyl ester; 2, 3-hydroxy dodecanoic acid, methyl ester; 3,
2-hydroxy dodecanoic acid, methyl ester. Adapted from Journal of High Resolution
Chromatography, 18, A. Kaunzinger et al., ‘Stereo differentiation and simultaneous analysis
of 2- and 3-hydroxyalkanoic acids from biomembranes by multidimensional gas chromatog-
raphy’, pp. 191–193, 1995, with permission from Wiley-VCH. (continued p. 419)

Jayatilaka and Poole analyzed fire debris by using headspace extraction followed
by multidimensional gas chromatography (22). Since petroleum products are com-
monly used to start ‘suspicious’fires, the samples are very complex, with misidenti-
fication of the propellant being common when analyzed by classical methods. In
addition because of the complexity of the samples, pattern recognition by humans or
by computers must be used to identify the samples, thus causing errors.
Multidimensional gas chromatography can be used to simplify the final pattern
recognition. For example, a second-dimension polar stationary phase can be used to
separate aliphatic and aromatic portions of a heart-cut from a complex chro-
matogram on a non-polar column.
The use of heart-cuts to analyze a sample of 90% evaporated gasoline is illus-
trated in Figure 15.9. Each of the lettered chromatograms illustrates the further sepa-
ration of mixture components which is not possible on a single column. The initial