Dear Researchers,
I am doing Gas Chromatography by using n-tetracosane as internal standard for un-targeted compounds , i am facing the following problem:
1: I run n-tetracosane as internal standard its retention time was 17.0 min, but almost in all my samples peak i have not found the internal standard peak at (+_) 17.0 min so why this?
2: My peaks are not straight so whats the problem?
Where will be the problem and how can i solve these?
Hafiz Muhammad Rizwan are you sure to prepare the internal standard with the correct solvent? And the concentration? Which is the higher and lower concentration of your standard curve? Are you sure that this component not start the degradation?
From what I can say from my limited knowledge about GC is that, your baseline is inaccurate i.e that baseline should be in a straight line, not a bell curve as seen in your sample, I'd suggest start wit a fresh batch of whatever you are using, so that his hindrance is gone.
Giorgia Pertile I have used the chloroform as solvent for internal standard and for my samples. 150ul/ul, ( i have tried 100, 150, 200, 250 ul/ul concentrations for internal standard but i select 150ul/ul)
Saurav Roy what you mean by baseline?
as i have mentioned in my question that why my peaks not starts from baseline, its my question
@saurav the baseline is straight in my picture, but the peaks are like a curve.
Hafiz Muhammad Rizwan try to change the temperature in the GC. Do you try to run this internal standard diluted in a different solvent?
@Giorgia_Pertile i have not tried the different temperature and different solvent
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