Page 337 - Multidimensional Chromatography

Industrial and Polymer Applications 327

The preseparation utilized a 5 m cyano column (250 cm 4.6 mm i.d.) and a
5 m silica column (250 cm 4.6 mm i.d.) in series, followed by GC analysis on an
SE-54 column (25 m 0.2 mm i.d., 0.33 m film thickness). The SFC system sepa-
rated the aviation sample into two peaks, including saturates and single-ring aromat-
ics as the first peak, and two-ring aromatic fractions as the second peak. These
fractions were selectively cut and then transferred to the GC unit for further analysis.
(Figure 12.20).
Another application of SFC–GC was for the isolation of chrysene, a polyaro-
matic hydrocarbon, from a complex liquid hydrocarbon industrial sample (24). A
5 m octadecyl column (200 cm 4.6 mm i.d.) was used for the preseparation,
followed by GC analysis on an SE-54 column (25 m 0.2 mm i.d., 0.33 m film
thickness). The direct analysis of whole samples transferred from the supercritical
fluid chromatograph and selective and multi-heart-cutting of a particular region as it
elutes from the SFC system was demonstrated. The heart-cutting technique
allows the possibility of separating a trace component from a complex mixture
(Figure 12.21).

Figure 12.20 SFC–GC analysis of a sample of aviation fuel: (a) SFC separation into two
peaks; (b and c) corresponding GC traces of the respective peaks (flame-ionization detection
used throughout). Reprinted from Journal of High Resolution Chromatography, 10, J. M.
Levy et al., ‘On-line multidimensional supercritical fluid chromatography capillary gas chro-
matography’, pp. 337–341, 1987, with permission from Wiley-VCH.