This is the chromatogram that I've received after running Supelco C8-C24 FAME mix in a TG-5MS (30m*0.25µm*025µm) of 5% phenyl methyl polysiloxane column. Kindly suggest the reason behind the baseline shift and how to prevent its formation?
I see NO problem with your baseline. What is obvious though is that you have a few scans per second (Hz on FID or scans per second on MS). because of the few scans, you see your baseline more like a zigzag plot rather than being a more flat baseline. Another important thing that is not shown here is the scale on the Y axis. If you are very close to zero on Y axis, then you can see the abnormalities on the baseline very clearly. However, if you zoom out, the baseline will be more stable and worry-less. If your peaks are too small and that's why you zoom in, try a smaller split ratio so that you can increase the peak area and you don't need to zoom in and look at the ugly baseline.
Mukhtar A Kareem Jaderson My data collection per scan was 10 for this run.
Also I had to zoom in because I received a massive solvent peak because of which the other peaks were not visible. I have tried different split ratios (mostly 1:10, 1:20, and 1:50). But the solvent peak didn't reduce much. Any suggestions on how to reduce the solvent peak would be much appreciated.
Unfortunately, you can't get rid of solvent peak on FID because the FID is always ON, even when the flame is OFF. What you encountered is typical in FID chromatogram. You'd see a huge solvent peak and you would need to zoom in in order to see analytes peaks. What I meant is that the picture in your question was taken inappropriately. You can zoom in and then use Windows Snipping Tool to take a better picture. What Noel said is also true, the elevated baseline at the end of the analysis is typical, because at the end of the run you would have the temp. program at the highest temp. set, which makes the column to bleed and raises the baseline. You can still integrate these peaks and make a good quantification out of them.
My only take is that you should increase the scan rate to have more points collected so that the peaks and the baseline are plotted in a better way.
Check these attached snips that I took for a full scale chromatogram on FID scan, then how I started to zoom in on the Y axis and then on the X axis to get to my tiny peaks compared to the huge solvent peak. My scan rate is 50 Hz, so make sure to make yours 50 Hz as well.
Also notice how my baseline was raised toward the end of the run, and I can still integrate the late eluting peaks and use them for quantification.
Noel W Davies Actually my chromatogram has a massive solvent peak (1000mv) due to which I had to zoom in to see the distinct peaks of my standard. Also, I've checked, my sampling points for each peak were 10. I have attached a screenshot of my entire chromatogram here depicting the Y axis . the small image on the top left is the overview of the chromatogram showing the huge solvent peak. Any suggestions about how to reduce it would be appreciated.
Again, solvent peaks are huge on FID and zooming in is normal. My only advice again is to increase your scan rate to 50 Hz and you are good to go. Your chromatogram is just fine.
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