Chromatography Forum

Good morning everybody
I'm researching the amount of PAH (poly aromatic hydrocarbon) in the gas and solid phase during biodiesel test in an underground mining in US.
We are using low volume sampling with quartz filter and PUF foam.
The laboratory found that the amount of PAH on both the sample is below the detection limit (we choose the EPA TO 13A method) due probably to the high dilution in the drift where we are sampling.
Considering that right now I cannot increase the sampling fow rate and the sampling time I'm wondering if I could get at least the total PAH concentration (without any speciation) on each sample.
My idea would be to propose to the lab to use a isothermal method at 300 celsius with a FID as a detector (extraction the sample preparation).
Any idea, suggestion ??

Thank you in advance

Emanuele Cauda

Hi Emanuele.
You could try this, It's free.
"Determination of n-alkanes and polycyclic aromatic hydrocarbons in atmospheric particulate and vapour phases in Oviedo, Spain, by GC-MS".
you can find it in:

J. Environ. Monit., 2000, 2, 218 - 222.
DOI: 10.1039/a910316n

good bye

Considering that right now I cannot increase the sampling fow rate and the sampling time I'm wondering if I could get at least the total PAH concentration (without any speciation) on each sample.
My idea would be to propose to the lab to use a isothermal method at 300 celsius with a FID as a detector (extraction the sample preparation).
Any idea, suggestion ??

I am wondering why you cannot increase the sample flow/time. Is it because you are measuring some kind of personal exposure ?

Ozone can cause serious degradation of the PAHs on the filter during the actual sampling. It can be one cause of "not detected". EPA TO13A (1999) as written does not acknowledge this. You need an ozone denuder, but this is not the complete answer either, because the denuder does not work very well at high humidity.

Summing an FID chromatogram is not a good idea, unless you have already proved it correlates with the speciated PAHs. Who is going to accept your results ?

Dr. Pat Sandra out of Belgium has just presented some work he has done on airborne PAG analysis in which he showed that PUF foam is not the ideal way to sample PAH's. You might try to contact him. I do not have contact information in front of me but if you cannot find him on the Web (and I suspect you can) I can look in a couple of places to see if I can get contact information. Basically, Dr. Sandra showed a consistent low recovery bias from PUF filters compared to the methods he was using.

Best regards.

AICMM Thank you for the contact name. I will, definitly.

Pueblito. I downloaded the file and I will read it today. Thanks

thank you all for your help.

Actually I started to struggle also with the lab manager. So far they provided LOD for each sample and each Analyte about 0.5 ug. So more or less a limit in the column of 1 ng. I asked other experts and they told me that a good GCMS should be able to provide 1-10 pg in column.

We will see.....the compromise is so far to work in SIM and not in FULL SCAN.

Emanuele