Problem with methane analysis

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desperated girl
desperated girl's picture
Problem with methane analysis

My conditions for methane analysis are
GC-2010/ Flame Ionizing Detector
Column Temp: Isolthermal 80 ºC
Injection: 200 ºC
Detecter: 200 ºC
He, N2, air zero and H2

When GC is ready for analysis, I inject my sample (methane gas) into injection port and then press "start". Normally (when I tested for agricultural chemical dissloved in solvent like haxane), its status will turn to "acquired" until stop time is reached.

But in this case, when I inject my sample gas, its status turns to "not ready" , "run" and then "acquired", repectively and remain "acquired" until injection has done.

I don't think it's normal but I don't know why it turns to be like this and how to fix this problem.

Please give me some advices!!!!!!

Best Regards

Dr. Analytical
Dr. Analytical's picture
First check all your system

First check all your system settings to make sure that there have been no changes.

What volume of methane are you injecting, and what column are you using?  What injection technique?

desperated girl
desperated girl's picture
I inject the volume up to 1

I inject the volume up to 1 ml into 20 umX0.53mmX30m. column by manual injection in spit ratio 0.2.

Do I have to increase my spit ratio into 5 or 10 or higher? But I'd like to retain my highest peak area, how do I adjust this condition to get the highest possibly?
Lately, I found another problem, when I inject 1 ml methane gas, my detetced peak have been spited to 2 peaks with a few different retention time. It never happened before and do not occur with 0.2-0.8 ml injection. What caused this problem? Do you have any ideas?
Please suggest!!!!