Chromatography Forum

Hello,

I am trying to calibrate DEHP on our GC MS, but I am having problems getting a linear curve. I can see the peak in all the runs I do, but the spiked concentration doesn't usually increase with the spike amount like it should. I have tried split and splitless and it doen't seem to help. The std is in methanol. If anyone can offer any advice as to things I should try pls let me know.

Thanks!

You might want to switch to DCM I had these problems with DEHP in IPA. You have an agilent? I would highly suggest using SIM mode and messing with the integration window to eliminate any tailing/fronting in the peak, especially if you want to decrease runtime, since DEHP typically takes a while to come out. I assume you already have a method.

Thanks I will try the DCM this time and see how it goes. Yes I have an agilent and I was running it in SIM mode. Yes, I have to use the EPA 525 method, mine is pretty close to that. Also I am seeing small DEHP peaks in my blanks, the only plastic it comes in contact with is PTFE and the JT baker speed disks used in the extraction, I have read the solvents can be contaminated with DEHP any experience with that?
Thanks.



[quote="gmattz"]You might want to switch to DCM I had these problems with DEHP in IPA. You have an agilent? I would highly suggest using SIM mode and messing with the integration window to eliminate any tailing/fronting in the peak, especially if you want to decrease runtime, since DEHP typically takes a while to come out. I assume you already have a method.[/quote]