Page 169 - Tandem Techniques

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the carrier gas and the raw sample was placed on the first column. The separation was monitored by the
mass selective detector and when the solutes of interest began to elute, the flow was diverted to the
cooled trap, and the solutes condensed and concentrated.

Figure 4.18
Multidimensional Gas Chromatography Coupled with
a Mass Spectrometer and the FTIR Spectrometer

The trap was made of deactivated fused silica tubing, 10 cm long, 0.019 mm I.D contained inside a
stainless steel tube 0.053 mm I.D. and was cooled to 50-100 K by a stream of cold nitrogen. When
collection was complete, the carrier gas was returned to the mass selective detector, and the temperature
of the trap raised to 200°C by passing a current through the heater. A second flow of carrier gas was
passed through the trap expelling the collected solutes onto the analytical column. The carrier gas used
in the second separation consisted of a mixture of 0.5% nitrogen in helium (in this case nitrogen was
used as the IR matrix). The column eluent was split and passed into two capillary lines; one 100 mm
I.D. that led to the FID, and the other 220 mm I.D. that led to the Cryolet FTIR