It depends on which sample-cleanup and what kind of instruments are used. In combination with GC-MS n-Hexane is fine especially if you do a conventional cleanup with (silica and alox) chromatographic columns.

By the way, if an evaporation step with a Rotavap is included You can use nonane as a non-volatile "keeper" to avoid that your samples are running dry.

Nonane makes a good keeper solvent or Dodecane both of which have low volatility. I tend to not allow samples to run dry and depending on final volume I add keeper at final N2 evaporation stage in the GC vial.

We made good experience with toluene as a keeper, it is very well suited for GC/MS....however, you have to keep an eye on it in the evaporation step...

According to my experience, the best solvent for making standards and keeping is iso-octane, and recently it is becoming popular nonane for their low volatility. However, it is recommended n-hexane for samples preparation on analytical procedure and GC-MS inyection. Another  point in consideration is that n -hexane is cheaper, also it is found in the market as pesticide grade to analyze PCBs.

I would use n-hexane as the solvent (I'm assuming you have already figured out your sample clean-up ). The biggest advantage of n-hexane is cost and this is something to consider, especially if you are working in industry. iso-Octane would also work, consider your temperature range and time between injections (in case of re-injections). 

Let us know how it works!

Dejan -

Use n-hexane, stock solutions from manufacturers will be fine when prepared in n-hexane.  They should be good for one year once prepared.  Store stock and prepared standards in freezer.  When you make standards from stock solutions make sure you allow to warm to room temp, and vortex prior to snapping ampule (very important).  See attached USEPA method TO4 for full method.

good luck

http://www.epa.gov/ttnamti1/files/ambient/airtox/to-4ar2r.pdf 

I've been using always n-hexane for the analysis of PCBs so I would recommend you to use it, especially because you would get easily to the final volume. n-hexane is, indeed, enough volatile to be evaporated fast enough

as stated earlier, I agree with colleagues, n-hexane for standards gives you more reliability and reproducibility on your results.

I've tried them myself and works perfectly especially that your samples are extracted, I assume with hexane.

good luck

I am still only making a plan and ordering standards etc. Haven't started experiments yet. This is great that I have opportunity to hear different experiences from you people. I really appreciate your time and help.Thank you very much!

I am planing to use Hexane and I ordered PCBs standards in hexane. Still don't know which solvents I m going to use for extraction, I am planing to try with DCM, Hexane,Acetone by using Soxhlet(PUF) and sonication (QFF). If you have some suggestion from your experience that would be great!

What I am going to do is collect PCBs on QFF and PUF extract- rotovap-filter-N2 evaporation and Inject (internal std). GC-MS SIM mode. I hope no cleaning will be required.

I agree with my colleagues. One of the best solvents considering cost, toxicity and availability is n-hexane. Nonane or dodecane as keeper is also recommend, however this may be sometimes challenging due to their higher boiling points which can limit their suitability for GC-MS (depending on injection and ion-trap or quadrupole temperature).

Hexane would be best from your available solvents. Making liquid standards for gas phase measuring of a high vaporization temperature compound families as PCB's is difficult. Please be certain your PCB mixture fully vaporizes and then stays in the vapor phase from standard input to measurement or you will have results difficult to quantify. 

Dear Dejan

Hexane is the best solvent for analysis PCBs with GCMS and Also  for GC-ECD analysis, and you can used the Hexane/acetone (1:1;v/v) for extraction PCBs from solid matrice.

good luck

https://www.researchgate.net/publication/279713128_Comparison_of_Soxhlet_Extraction_Microwave-Assisted_Extraction_and_Ultrasonic_Extraction_for_the_Determination_of_PCBs_Congeners_in_Spiked_Soils_by_Transformer_Oil_%28ASKAREL%29

Article Comparison of Soxhlet Extraction, Microwave-Assisted Extract...

In 50 ml of sample was added 2 ml hexane. The mixture is put into an ultrasound bath for 2 hours. Spin at 2500 rpm 10 minutes or more.

Injected into the GC-MS 1 microliter  of the matrix thus obtained.

Good luck with that

Mihai Ionicã

n-hexane is the best solvent and can be used

nonane. All standards we use (PCBs and PCDD/Fs) are sold in i-octane but then we use nonane for all the working solutions. It is stable for sampling solutions to injection solutions.

Nonane is a good solvent especially for the standards. There is nearly no loss of solvent by evaporation, e.g. if the vial is not immediately removed from the autosampler after injection. For samples I would recommend n-hexane which allows to evaporate the sample if needed.