Chromatography Forum

Hi all,

I am using Agilent GC 7890 A/5975C MSD. Currently I'm having a problem in increasing of baseline of chromatograms for several samples. Below is the problem statement.

Problem statement:
- Unable to maintain baseline of chromatograms several sample.
The abundance for baseline for first sample is around 5k while for the next sample is around 20k.

Refer below link of the chromatogram:
http://mam.minaik.com:9998/public/downl ... sopdLIs%3d

I had try flushing with solvent until the baseline become stable. The baseline would gradually become higher after running sample.
Any idea to solve this problem?

TQ
MY Low

...
Refer below link of the chromatogram:
http://mam.minaik.com:9998/public/downl ... sopdLIs%3d
...

Are you sure that this is the link you wanted to paste ?

Hi,

Sorry due to the server down.
Right now I had tried to click the link, it is already OK.

Regards,
MY Low

He is saying that the link you provided does not take us to where you want us to go. I concur with dblux_, that link takes us to somewhere that does not make sense.

The link does work. By clicking it you see a page with a link to "info.xlsx". Clicking on that link downloads an excel file with the chromatograms pasted onto the worksheet.

(I scanned the file with malwarebytes and avast prior to opening it up. It came up clean. But of course you should do the same prior to opening it up.)

When I clicked on your link the first time, I didn't get what you described. This time, I did get it.

What you are seeing is normal in my experience. Real samples always contain more "stuff" than standards. In your samples, many of the peaks are not well resolved from each other. In most GC detectors, those signals are additive.

Unresolved Concentrated Analytes = Longer time back to baseline.

Your standard appears to be quite dilute. If you are disturbed by the large baseline rise in your chromatograms, you can put less sample on your column. This is achieved by 1) injecting less, 2) increasing your split ratio in the inlet, or 3) diluting your sample with more hexane. Any of these approaches will likely cause you to not be able to detect the less concentrated materials in your sample.