Loss of resolution in GC-MS

[ybezjak]

Help!!! I am running PAH analysis on GC-MS, and I have 2 problems that I can't solve. First, I am losing resolution towards the end of each run and cannot firgure out what is causing this. Second, there is a loss of response for the internal standard in each sample. In the calibration standards, 20ug/ml internal std. gives a response of 9000, but the same concentration in the actual samples gives only half that. Is this some sort of matrix effect?

[Jing]

Hi,

I'm doing research on PAH with GC-FID.

Can you please tell me what kind of internal standard you are using? What kind of sample are you dealing with, water or sediment, or both? What is your extraction procedures? What solvent do you use as the final solvent?

Please share the knowledge with me. Thanks!

Jing