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Calculating on-column amounts for purge and trap
Posted: Sat Nov 13, 2010 12:19 pm
by tangaloomaflyer
How I do calcualte the on-column amount of analyte for purge and trap GCMS?
Presumably I need to know the purge and desorb efficiency?
thanks
Posted: Mon Nov 15, 2010 7:04 am
by Peter Apps
This can rapidly become a circular argument - on-column amounts are calculated on the basis of sorbtion and desorption efficiencies, and split ratios, and efficiences are calculated as on-column amounts vs standards added to traps
You can calibrate peak area vs on-column amount using splitless or preferably onc olumn injections of standards in solvent, then the peak area from the P&T runs gives you the on-column amount.
Peter
Posted: Mon Nov 15, 2010 2:05 pm
by AICMM
tangaloomaflyer,
Re: purge and desorb efficiency, for most compounds (the ones that purge well) I would argue no, you don't. But if you want I would propose the following. Purge a standard and run it. Don't allow your trap to bake. Re-run the trap on the next run. Look at the area recovered on a subsequent desorb. Then re-IS your standard water with just a bit of fresh IS in water and re-purge and re-run the same water.
Best regards,
AICMM