| dc.description.abstract | The biggest limitation to conventional gas chromatography (GC) is limited peak
capacity, making the analysis of complex mixtures a difficult or even impossible task.
Comprehensive two-dimensional gas chromatography (GC×GC) significantly
increases peak capacity and resolution, improves sensitivity and generates structured
3D chromatograms. This is achieved by connecting two columns coated with
different stationary phases through a special interface (modulator). The interface
samples the first column effluent and periodically injects fractions of this material, as narrow injection pulses, onto the second column for further separation. Commercial instruments achieve this with cryogenic agents. Since this expensive approach permits only in-laboratory analysis, the development of simple, economical and field-capable GC×GC systems is in demand.
This report summarizes the fundamentals governing GC×GC separations and a brief
history of technological advances in the field. It also documents the construction of
a simple interface, devoid of moving parts and cryogenic consumables, and hence
highly suitable for field analysis and monitoring applications. Evaluation of the
interface suggests on-par performance with more complicated cryogenic modulators.
GC×GC separations of technical mixtures of fatty acid methyl esters (FAMEs),
common environmental pollutants (EPA 8270), polychlorinated biphenyls (PCBs),
pesticides (toxaphene), as well as selected essential oils and major distillation
fractions of crude oil indicate very good performance. Most notably, the interface
prototype was applied for the first ever time-resolved on-site analysis of the semivolatile organic fraction of urban air particulate matter (PM2.5). | en |
