If there is no chloroform at the end of 2 h then you clearly have a leakage problem. Check the rim of your vials for chips and imperfections and use a new seal or cap.

Dear Rohan Sachan,

Unfortunately, I cannot understand the point of your method. Of course, in order to perform a GC-MS analysis of PAH, I have to extract the analytes from the sample. PAH are very soluble in organic solvents such as chloroform. The addition of acidic methanol makes no sense to me since PAH are neutral molecules, but methanol is also GC compatible. why does water have to be added to separate the organic phase/chloroform? Without adding this water, you can inject the extract directly into a GC-MS system.

Unfortunately, you do not describe the matrix from which you want to determine the PAH.

For aqueous samples I would prefer a solid phase extraction as sample preparation (SPE). This gives you high enrichment and therefore low detection limits.

Solids can be extracted well with a house variant of the accelerated solvent extraction (ASE).

To do this, take a headspace vial (10 or 20 ml), weigh the sample, then add the organic solvent and seal the vial tightly. Place the vial in an oven at a temperature approximately 15-20°C above the boiling point of the solvent. Properly sealed headspace vials are pressure-tight up to 3 bar. In my experience, other glasses are not suitable because they cannot be closed tightly enough. The solvent does not boil due to its own vapor pressure, but the rate of extraction doubles for every 10° increase in temperature. I recommend for Chloroform with a boiling point of about 61°C a extraction temperature of 80°C for 30 min. To control losses of Solvent you may weigh the filled Vial before and after extraction. You can calculate the loss of volumen using the density of your solvent.

You can analyze the extract directly or concentrate it further by specifically evaporating the solvent.

I hope I was able to give you some good suggestions

best regards

Joachim Horst