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TPH concentration with GC-FID

Posted: Fri Jan 04, 2019 4:26 am
by Yoonjoo
Hello, I'm trying to evaluate the TPH concentration of the soil sample(diesel contaminated) using the GC-FID.

To test the GC method and condition, I purchased TPH reference reagents with 17 alkane components(C8-C40) in it, all same concentration (500 ppm).

I got clear 17 peaks, and each of their areas is similar around a value of 300.

Next step is to measure the "real sample", but now I run into difficulties.

Since I used the TPH reference reagent for the GC test, I have no information (retention time, area...)about other compounds in the diesel such as PAHs...

Here are my questions:

1) How can I determine the TPH (Total Petroleum hydrocarbon) concentration, unless I get information about all the peaks for the compounds in the diesel? Now I got only 17...

2) I got 17 peaks with the same value of area around 300, with the reference reagent (500 ppm, C8~C10 alkane). Can I assume that other components in diesel within that range also show similar peak? (Area 300 for 500 ppm)

I just want to know the TPH concentration, not each of them respectively.

I'm waiting for help of someone who has measured the TPH concentration with the GC-FID. I'm using HP-5 column (not HP-5ms) :(

Re: TPH concentration with GC-FID

Posted: Mon Jan 07, 2019 8:37 pm
by cjm
There's guidance in this forum about hydrocarbon range calibration. Also check out methods 8015, 8100, 8000, and CT ETPH for more. Your calibration table needs to have an entry for the summation of all those 17 peaks, then when running an unknown, integrating from before C8 to just after C40 will give you your TPH value.

Re: TPH concentration with GC-FID

Posted: Wed Jan 16, 2019 12:18 pm
by varossf
or contact me via my email