Our cave sampling method coupled with sample pre-concentration
using a multi-bed sorption trap (MBST) prior to injection onto
a commercial GCGC-FID has proven to be a successful tool for
screening, fingerprinting, and comparing cave atmospheres.
Results from two different Texas caves compared to a background
air sample from within a laboratory (normal building environment)
show variation in volatile and semi-volatile compounds.
Furthermore, the two caves show differences in chromatographic
signals and more specifically differences in the amount and abundance
of signals corresponding to different chemical families (i.e.
suspected aliphatics, aromatics, polar compounds, etc.). To
improve upon the method in the future, mass spectrometry detection
will be implemented with the commercial GCGC instrument.
Effluent will be diverted through a heated transfer line into an electron
impact source and ions will then be extracted from the source
into a time-of-flight mass spectrometer. However, it should be reiterated
that the power of GCGC for providing chemical information
for differentiating and fingerprinting atmospheres can be
seen without the use of a mass spectrometer and can be used to
glean information about likeness and diversity of atmospheres.