About EPA 525.2 method, detection/quantification limits

[ricard]

Hello,

The MDL for some PAH in EPA 525.2 method is about 0,1 ppb(ug/l). Now, European legislation establishes around 0,001 ppb for some PAH (maximum allowed concentration in superficial waters). I'm usisg a 7890A GC/ 5975 MS, with a previous solid extraction (SPEDEX_DRYVAP). My question is related to the MDL, can we, whit this method achieve the detection/quantifications limits around 1 ppt. The GC/MS with SIM, permits to detect/quantificate withe some confidence around the 0,5 ppb of PAH analyte concentration. Then, with a solid extraction with a factor of concentration of 500-1000 and and assuming 100 % recovery, we could achieve the legislation demands?¿?¿?¿?!!!

perhaps I do some basic mistake in "all of this". Perhaps, the method doesn't allowed if we adhere/stick to it literally?¿?¿

Please some help, thanks in advance.

[X]

yes, you can, if you can see 0.5 ppb with SIM, then you can get 0.5 ppt limit in the 1L drinking water, say you extract 1L into 1 mL.

[Bigbear]

I have played around with sim methods for the "ECD" compounds in 525 and they offer a decade or more in sensitivity gain. I would suspect thet the PAh's would work as well.
If I'm not mistaken you can run SIM/SCAN on your instrument.