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Low Level SIM and PAH's

Posted: Sat Jun 16, 2007 3:48 am
by sllimbri
Does anyone run PAH by SIM on an Agilent 5972 w/5890GC? If so, what is your calibration range? What column are you using? I would like to be able to calibrate down to 0.05ug/ml. Is this possible on a 5972?
Thanks.

Posted: Sat Jun 16, 2007 12:44 pm
by Schmitty
In my experience a 72 is not any less sensitive than a 73. I have done PAHs on a 73, taking conditions/column from a Supelco/Restek catalog. It was a few years ago that I worked on it, but I think I recall my low standard was 1 or 3 µg/mL in DCM. I was using one quant ion and two qual ions, I believe.

Not low enough

Posted: Mon Jun 18, 2007 1:47 pm
by sllimbri
1.0ug/ml is not low enough. Is it possible to calibrate lower and how is it done?

Thanks

Posted: Mon Jun 18, 2007 3:16 pm
by Schmitty
Haha, sorry...wrong units. I was at 0.001 or 0.003 µg/mL for a low level standard.


edit: I reread your question, and you ask "how" to calibrate the instrument. Have you used a GC or GC/MS before? If you have, then the PAHs are the same as any other compound, with their own quirks. If you have not used a GC, then you have much more to learn.

I had no special technique for my analysis, that I recall. I know clean solvents were a must, since I did signicicant concentration of my extraction solvent (toluene).

low level sim

Posted: Tue Jun 19, 2007 3:30 am
by sllimbri
By "How" I mean method parameters. Yes...I maintain four gc/ms's daily for the last 6 years.

Thanks

Posted: Tue Jun 19, 2007 12:32 pm
by Schmitty
Well, for method parameters, I would work from those in a catalog. I like Supelco, and they have 10-12 good examples in the current (2007-2008) catalog. Page 345 is a great example of the 525.5 EPA method.

It has the GC conditions listed, and they are all fairly nominal. High injection port temp, low oven starting temp, ramping to 330C, DB-5 column. Other than that, I don't know what to say...it's all pretty basic, nothing special. :)

Good luck