No (H) Carrier Gas

[wetlander]

The gas chromatograph (an old Shimadzu GC14-A) I use for my PhD research is being used by several people out of necessity. This morning, I came into the lab to find that the researcher working on N20 had the GC on, and the carrier gas, hydrogen in this case, was not flowing. I immediately checked the valve, to find it partially open, but not flowing. After I opened it all the way, the gas began flowing again. I checked the activity log and the chromatographs, and the gas had not been flowing from 2:30 a.m. through 11:00 a.m. I don't use any of the same columns, gases, or detectors as the researcher working on N2O, but my PhD is riding on this GC. Is it ruined? And what should I do to check for damages? Any advice would be more than helpful. Thanks!

[Schmitty]

What was the column phase and the oven temperature?

[wetlander]

The oven temperature was at 40 degrees C. I'm not quite sure what a column phase is - I'm trying to find information on that now. But I can tell you that we use a Porapak-Q 1.8-m column, and we analyze gas samples from wetlands for nitrous oxide and methane. I'll post more if I find what the column phase is.

[chromatographer1]

A porapak Q column with air at 40°C all night should not be harmed.

Q polymer ages (oxidizes and crosslinks) with time in use and even after many weeks of use will still give consistent separations.

My guess (not knowing if any high temperatures were reached when the column was filled with air) would be that no harm was done.

If you are really concerned about your PhD then invest in a new column, but first test the column with any test or calibration mixes you might have on hand.

If the temperature was held at 200°C overnight my answer might be different.

best wishes,

Rod

[chromatographer1]

A porapak Q column with air at 40°C all night should not be harmed.

Q polymer ages (oxidizes and crosslinks) with time in use and even after many weeks of use will still give consistent separations.

If the column is glass examine the packing inside it. If it is a light yellow or off white the packing is fine. If it is brown it is not fine.

My guess (not knowing if any high temperatures were reached when the column was filled with air) would be that no harm was done.

If you are really concerned about your PhD then invest in a new column, but first test the column with any test or calibration mixes you might have on hand.

If the temperature was held at 200°C overnight my answer might be different.

best wishes,

Rod

[wetlander]

Hi Rod,

Thanks for the information and advice. I'm positive that the oven didn't heat to over 40 degrees C, so that seems a good thing. I'll definitely run some standards to test the column and detectors before running samples again. Thanks!