Chromatography Forum

We use gas chromatography, there is no flow system. We use a shock tube, and after the shock, a valve opens and a sample flows through tubing and through the sample loops of 4 detectors and eventually to a vessel. We measure the pressure in the lines (just above an atmosphere) and inject the samples. Right now we have all the sample loops at 150 deg C, should they be at a higher temperature. We are able to go higher, but that also means we would need to raise the temp of all the lines (treated tubing).

What determines the temperature of the sample loops? I posted earlier about the calibrations of n-dodecane. I was wondering if either the temperature of the tubing/sample loops are to low.

I can not figure out your experiment, but the loop temperature is determined by: 1. to prevent condensation of the sample, 2. Not to different from the initial temp of the column (to prevent the change of volume) and 3. not to high above the tolerant temp of the valve (loop and valve are normally at the same temp).

I'd be careful as you may exceed the temperature of the valve rotor above 150. Maybe you're not using an actuated valve and then it's won't matter.