Chromatography Forum

Anyone have experience with this?

This is my first post and also my first attempt at using the double shot pyrolyzer and GC. I've verified that the GC works just fine and the heating elements of the pyrolyzer works fine. The column head pressure is stable (=> no leaks I believe). Yet I do not see any peaks turning up.

The pyrolysis run is a single shot (at 550 deg C), Interface is at 300 (auto) and the inlet is kept at 300 too. The method is splitless, flow rate of 1.5 - 2.0 ml/min over the column, starting at 70 deg up to 280 deg Celsius at 10 deg/min. Any other information can be provided.

I've ensured the column (a relatively new HP-5 that has been conditioned and tested) works fine with no breaks or such.

Any help with this is appreciated.

Although I have no personal experience of using this sampler, we have several customers using the Frontier sampler without problems. I would make the following suggestion.

Have you actually measured the flow coming out of the column when it is connected to the sampler. A common problem is the following. You input the dimensions of your column into the 6890, and it calculates the pressure needed to give that flow. However, it assumes that electronic flow control is going directly to the column and detector. If the carrier flow is going through the sampler before it gets to the column, there will be a pressure drop in the sampler. If this pressure drop is too high, it is possible that the pressure that the 6890 caculates is not high enough to give a flow. To try this theory out, just increase the 'flow' by a factor of 2 or 3 and see if any peaks appear.

Gasman

Thank you, will give it a try.