Page 155 - Tandem Techniques
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automatic. The device was used extensively for the separation and identification of essential oil
constituents.
Figure 4.4
Chromatogram and Spectra Obtained
from the First GC/IR/MS Triplet System
Modern GC/IR Systems
Light Pipe Interfaces
IR spectrometers are generally much less sensitive than mass spectrometers and, as sample sizes are
often very limited when used in tandem with chromatographic instruments, special techniques must be
employed to utilize the maximum sensitivity that is available. This is true even with the modern FTIR
instruments although they can, indeed, be much more sensitive than the older dispersion type
instruments. One device that is commonly used to increase the sensitivity of the IR instrument when
used to examine vapor samples in a gas, (e.g. those eluted from a gas chromatograph) is the 'light pipe'.
