Chromatography Forum

Dear friends,

I want to analyze PAHs (Poly Aromatic Hydrocarbons) in water samples , I applyed Standard method 2005, method number: 6440B.
In which it says :
"Extraction by means of separatory funnel : Normally use a sample volume of 1 liter.For sample volumes of 2 liter use 250 , 100 and 100 ml volums of methylene chloride for the serial extraction of the base/neutrals and 200 , 100 and 100 ml volums of methylene chloride for the acids"

but in next paragraph it says that we should add 60 ml of methylene chloride in three times..... !!!!
I confused if I have to use 60 ml or those 250, 100 &100 ?

Could anyone help me?
Or even introduce me of any other method for PAH analysis in water? (EPA or ASTM method)

Thank you for your help.
Faithfully yours,
Maryam

Maryam, please consider SPE for concentration of PAHs in water, e.g.

EPA METHOD 550.1
DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN DRINKING
WATER BY LIQUID-SOLID EXTRACTION AND HPLC WITH COUPLED
ULTRAVIOLET AND FLUORESCENCE DETECTION

I personaly use PAH aqua SPE columns manufactured by Baker and elute PAHs with 3 + 3 + 2 ml of methylene chloride. Then I evaporate solvent to dryness and dissolve PAHs in 1 ml of ACN. That's my analytical sample concentrated by a factor of 1000.

Wojtek

PS1 - IMHO 3 x 60 ml is more realistic than 250 + 100 + 100
PS2 - If you are not limited to EPA or ASTM methods you may as well check ISO 7981-2 standard "Water quality -- Determination of polycyclic aromatic hydrocarbons (PAH) -- Part 2: Determination of six PAH by high-performance liquid chromatography with fluorescence detection after liquid-liquid extraction", link to abstract:
http://www.iso.org/iso/en/CatalogueDeta ... 60&ICS3=50

dear friend thank you from your guid.
Please say for me about SPE columns and describe extraction method.
do you use from K-D concentrator ?

dear friend thank you from your guid.
Please say for me about SPE columns and describe extraction method.
do you use from K-D concentrator ?

I use JTBaker SPE PAH aqua 6 ml columns:

http://www.jtbaker.nl/bin/chroma_gevond ... nguage=EXP

The whole method is on JTBAker site:

https://www.mallbaker.com/techlib/docum ... n-510.html

I don't use K-D concentrator, I simply evaporate solvent in gentle stream of nitrogen.

Hope you'll enjoy this simple method.

I have used SPE with the chromatography being done on a column specifically designed for PAHs.

Some tips- do not use compressed air for evaporation as you will pick up PAHs from the air. Use pure nitrogen.

It is vital to thoroughly degas the HPLC media as oxygen quences the fluorescence signal.