In recent years there has been a growing demand on fast screening systems for classification of samples using their volatile composition. Typically, these samples can be analyzed by either static headspace or thermal desorption analysis. Several different approaches are possible, but common to many of the systems is that a chemometrics software package is used to explore and classify the data. The present paper compares three instrument configurations: a “Fast” GC system, an “e-nose” headspace mass spectrometer, and a conventional headspace GC-MS, which can also be used as an e-nose or Fast GC. This paper will discuss these three approaches to rapid sample classification, illustrating the differences using typical commercial examples.
The three different approaches all have pros and cons that make them more or less suitable for any given application. The Fast GC and the conventional GC-MS have the advantage of providing complete chromatograms with separation of compounds. The GC-MS is the most versatile system because it can be used for both liquid and headspace measurements. In addition the headspace GC-MS configuration can also be used as an e-nose or in a Fast GC mode. As long as no separation is done, the e-nose and the headspace GC-MS in the e-nose mode have similar throughput (2 to 4 minutes per sample) and the Fast GC has the longest analysis time (approximately 11 minutes from sample to sample). When cost is a factor, Fast GC is the least expensive, while the headspace GC-MS with e-nose capabilities is the most expensive system.
