Chromatography Forum

Hello,

I have a question, if can you help me I would be grateful.

I'm having trouble with Nonpolar GCMSD. Some peaks come out spread and the baseline going up. My column has just changed and my tune values ​​are very good.

I leave a sample image below.



Do you have any suggestions?

Thank you.
Samet YANKAC

To me, looks like a chromatography issue, not MSD. Looks like you have some polar/tailing peaks from non-polar components.

Firstly, thank you for your reply.

I think something else is triggering it. Because when I compare it with other nonpolar devices, the peaks seem not to spread. This problem was experienced 3 weeks ago and I had changed the column. The problem was solved but it started to recur again.

Thanks.
Samet YANKAC

If changing the column corrected the problem then it returned after running more samples, then it sounds like something in the samples is contaminating the inlet or head of the column.

Does removing a loop of the column change the peak shapes?

For some tests that I do I have to do inlet/column maintenance daily, which includes replacing the inlet liner, cleaning the inlet with a solvent soaked swab, and removing about 100mm of column. If it requires removing that much column every day I use a guard column in front of the main analytical column to extend the life of the analytical column. Depending on the test, I can get by with not removing any of the analytical column before the 1m of guard column is used up but sometimes after a few trimmings of the guard column I have to remove it and take off 100mm of analytical column then replace the guard column.

Are you injecting with split injection or splitless injection?
What type of injection port liner are you using?
What is the injection port temperature?
What volume of sample are you injecting?

More information will help us diagnose the problem.

If changing the column corrected the problem then it returned after running more samples, then it sounds like something in the samples is contaminating the inlet or head of the column.

Does removing a loop of the column change the peak shapes?

For some tests that I do I have to do inlet/column maintenance daily, which includes replacing the inlet liner, cleaning the inlet with a solvent soaked swab, and removing about 100mm of column. If it requires removing that much column every day I use a guard column in front of the main analytical column to extend the life of the analytical column. Depending on the test, I can get by with not removing any of the analytical column before the 1m of guard column is used up but sometimes after a few trimmings of the guard column I have to remove it and take off 100mm of analytical column then replace the guard column.

Are you injecting with split injection or splitless injection?
What type of injection port liner are you using?
What is the injection port temperature?
What volume of sample are you injecting?

More information will help us diagnose the problem.

Thank you for your answer.

I do not give samples with high viscosity. Since I work in a Polar-Nonpolar way, I think I should have experienced the same problem with Polar.

What is the protection column?
I am using split injection and 0.5 µL injection.

On October 18th I solved the problem by doing the following:

-I changed the column.
-I checked the EPC.
-I cleaned the EM Volt with IPA.
-I cleaned the ION Source.
-I renewed the Septa inside Merlin.
-I renewed the inlet line.

After doing these steps, my problem was fixed.