Nitrogen as carrier gas for pyrolysis

Nitrogen can also be used with the OPTIC inlet and GC-MS for pyrolysis.

 

Empirically, we found that there is a big impact of the external heat transfer on the pyrolysis inside the OPTIC inlet. Since Nitrogen has a much lower thermal conductivity than Helium (5.8 times), it takes longer to heat the sample to the pyrolysis temperature.

When OPTIC is used for pyrolysis with Helium, a typical time of 10 to 20 seconds is enough to break the sample down. But when Nitrogen is used as the carrier gas for the same application, it requires between 40 to 180 seconds (depending on the sample) to enable the pyrolysis process.