analysis procedure for TPH & VOC in swab sample
Posted: Wed Jun 20, 2012 5:34 am
by organicchem
Hi All
Could you please tell me how to carry out sampling from metal surface by swabing. I search net by couldn't find any appropriate procedure. Also i want to know how to calculate and to report the the results.
Re: analysis procedure for TPH & VOC in swab sample
Posted: Wed Jun 20, 2012 2:24 pm
by Steve Reimer
In the most general terms, measure a set area, wipe with appropriate material, fold material and place in vial or jar. In the lab add a measured amount of solvent to extract analytes of interest and analyze a portion of solvent. Report the amount of target analyte on wipe (our default) or amount per area (requires accurate area measurement).
Which material is appropriate for the wipe and whether is should be dry or contain solvent depends upon the surface, the targets and the analysis method.
I have tried wiping a surface for volatiles (BTEX) with varied sucess. Porus sufaces hold volatile targets the best but don't release them to the wipe material well. Non-porus surfaces don't retain volatiles but are easy to wipe for semivolatiles.
Oils on metal or non-porus paint work the best. US-EPA defines a procedure under TSCA for surface wipes to detect PCBs.