Please could anyone share their experience how you desiccate filters after sampling. Do you apply vacuum, i am worried will I have some losses from the filters due to vacuum.
Thank you!
Dear Dejan,
Assuming you sampled on glass fibre filters, then it's better not to use vacuum to dry them, or use higher temperatures above 20°C. Some PAH's like naphtalene are volatile, but still very less at 20°C. Mostly PAH loaded filters are not dried before analysis, but equilibrated for 24 hours at 20°C and 50% RH in a climate control room, before and after sampling. Should you be interested in the volatile PAH, then you should backup your filters with Tenax tubes.
Hi Dejan,
I am not sure if I understood your question correctly, but I only desiccate my filters when I need to measure collected mass. For PAH analysis I never do this step unless required, as the losses, as you well point out, can be considerable for the semivolatiles. I usually take the filters out of the freezer, extracted with an organic solvent mix and analyze them (with a previous gentle reduction of volume if needed). Hope it helps.
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