Hello Della!

In our lab we use glass containers in order to minimize the possibility of interaction between sample and container walls through the procedures. (Not only in the case of lipid extraction procedures but also during bone collagen extraction).

Does anyone have literature on the subject? 

Hello Celeste,

Thank you for your response. Just one quick question, I have noticed that glass vials/jars come with either metal foil, plastic or rubber 'stopper' parts. What is the better material to use, to avoid any issues with degradation of the seal or a chemical reaction with the chloroform/methanol?

I have searched the literature but I have been unsuccessful so far in finding an answer.

Regards, Della

Hello Della, 

typically, glass works better than plastic. However,using glass vials is not always practical. Companies provide detailed information about the utility of different types of vials,including plastic. You can always  give them a call or email them for further details. 

Hello Della,

We use laboratory film to cover the glass containers during the procedures but since our samples are treated for only 24 hours, I do not know what could happen in case you need to leave them for a longer period of time.

Paschalis has a valid point here, you could ask the provider. Please keep us posted if you do!

Regards,

Celeste.

Thank you Paschalis, Celeste and Jon,

I am working with shearwater feathers which are reasonable oily.  I will clean in chloroform/methanol for 24hrs and then replaced with solution again for a further 24hrs.  I am looking at carbon and nitrogen signatures. 

Cheers,

Della

In general, when doing a solvent extract of organic material we always use glass.  Chloroform/methanol will dissolve most plastics. adding modern carbon of indeterminate isotopic value to the sample.

Hi Della,

you should work with glass. With CHCl3/MeOH you will extract and dissolve partly plastic tubes and you will find it in your analysis. We extracted roots for severel days to afterwards analyse the biopolymere suberin in the root. We used glass vials with single use teflon seals in the cap which worked quite well. We hardly found contaminations in our GC-MS analysis afterwards.

Best, Frederik

Thank you Frederik and Valerie for your help.

Regards,  Della

I second the comments favouring glass over plastic. Using glass will eliminate any potential for contamination.  My question however would be why you would want to "store" the feather samples while degreasing as your questions about lids for glass vials suggests?

While keeping cut-up feathers with a CHCl3/MeOH mix in glass vials may not incure the risk of contamination from the container, it will increase the risk of solvent molecules "creeping" into the keratin matrix.  Getting rid of solvent contamination sitting in the "crystal" lattice of keratin will take several days exposing samples to high vacuum.

To degrease feather samples prior to 13C and 15N analysis you are better off washing / rinsing finely cut feathers repeatedly with CHCl3/MeOH followed by repeated rinses with de-ionized water.  If your samples are particularly oily you could use a CHCl3/hexane (or heptane) mix first before moving on to CHCl3/MeOH.

These wash / rinse cycles (no pun intended) are best carried out using a glass filtration unit (see link below).  Place your sample inside the funnel on the filter frit and add your solvent mix (say 20 mL).  Stirr / agitate with a metal spatula and then switch on the vacuum pump connected the side neck of the Erlenmeyer flask to suck the solvent mix through the filter frit.  Switch off vacuum and repeat this step several times (how often depends in degree of oilyness but 3 to 5 times should suffice). Now repeat this procedure with de-ionized water.

http://www.coleparmer.com/Product/Labglass_Replacement_Funnel_for_Filtration_Assemblies_47mm_dia_300_mL/EW-34509-38

Once you're finished washing, dismantle the filtration unit and put the sample into a glass vial.  Even though the material will look dry, it still needs to be dried down completely prior to analysis, ideally in an evacuated desiccator containing a strong drying agent (phosphorous pentoxide).