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Gasoline Range Organics by HeadSpace
Posted: Tue Dec 18, 2007 10:03 pm
by ableich
Has anybody here analyzed Gasoline Range Organics in Water matrix by Headspace mode using the CTC CombiPAL. If so, I'm looking for an application note to get started. I"m looking to detect at the range of 50 ppb to 1 ppm. For lower levels, I'm looking to do SPME (0.1 ppb - 100 ppb).
Thanks,
Alex
Posted: Wed Dec 19, 2007 2:03 pm
by chromatographer1
I would be concerned with looking at C4-C12 hydrocarbons with a total of only 50 ppb using headspace.
Why don't you use a 3 to 15 meter 0.53mm ID fused silica 1µm film Equity 5 or similar phase capillary and do a direct injection?
Use a large ID liner DIRECT injection (not splitless) liner or use a cold on-column injection of 0.5µl or less?
Otherwise I would try to use a high temperature headspace analysis with total evaporative sampling if possible. In other words, only use 5 to 25 microliters of sample heated to 120° or more and inject 1cc volume directly onto the column.
Good luck,
Rod
Posted: Thu Dec 20, 2007 4:29 pm
by AICMM
ableich,
The problem is that gasoline is a multi-component mixture. Therefore, you are looking for 50 ppb spread out among 20-50 components so each one (except for the biggies, BTEX) is at a very low level. The same SPME stuff you are looking at for BTEX would be very applicable to GRO. Did you look at Varian's application notes on this?
PPB headspace of BTEX with PID or AID is pretty straight forward but I have never looked at how far down I can go with GRO.
Best regards.