Lipid extraction

[Odto]

Hi,

 

Can anyone help me with this question. Why does the Lewis et al Modified Bligh & Dyer method (and many more) use vast volumes of solvent >80mL for 500mg of sample for? I have read many articles, including the Folch method, I can't get access to the origional Bligh & Dyer unfortunately, wherein may lie the answer. There seems to be no standard rule to the volumes used/sample mass or volume however I have seen many variations.

 

Having discussed with a chemistry expert, I am biologist with interest more specifically at the molecular and biochemsitry level, the volume has been adjust to max of 25ml/500mg sample. But without any clarification. I can't find the answer to my question after fruitless searches apart from an ad hoc mix of differeing volumes used.

 

Is it something to do with equilibriums changing and extraction becoming more efficient with greater volumes?

 

Any help in answering this, or directing to relevant material which may help will be much apprecaited!

 

Odto

 

PS - I am using a simple method which is non-modifying to lipid structure, unlike FAME, the lipids are to be used in subsequent binding assays so must remain in native form.

 

 

[spin-1/2-nuclei]

Disclaimer:

Sorry I'm just a chemist, so I'm not familiar with the procedures you've mentioned above. My research focuses mostly on the design and development of novel chemical reactions and we rely heavily on computational chemistry/molecular modeling so I spend about half of my time doing wet chemistry and the other half of my time doing computational chemistry. So, in short I am probably not the best person to help you with this, but since nobody else has come along yet, I thought I'd try to help.

 

Hello,

 

Based on what you're describing I think the chemist probably decided you'd only need 25 ml of solvent to dissolve your 500g of lipid and accomplish the rest of your tasks. As long as you're not currently having problems with your data I think it should be okay.

 

hopefully this helps, but if it doesn't post again and I will see what else I can do to help. Hopefully an expert familiar with your field will come along.

 

 

Best of luck with your research.

 

Cheers

[Odto]

Hi,

 

Thanks for this. I'm going to run the experiment using stated volumes but also at two other much lower volumes, one at my 25mL and see if this has any affect on the total lipid extracted from the biomass. I should be able to see from this if the volume has an affect then... then to discover from the literature why!

 

Cheers

[hypervalent_iodine]

I found this review in a quick search I did this morning, http://www.mendeley.com/research/evaluation-of-extraction-methods-for-recovery-of-fatty-acids-from-lipidproducing-microheterotrophs/. Unfortunately I didn't have time to read it, but the abstract suggested that volume of solvent doesn't have an affect on the extraction yield. Hope that's of assistance!

[Guest meercy]

 

 

 

• Lipids occur in tissues in a variety of physical forms, but the complex lipids are usually constituents of membranes, where they occur in close association with such compounds as proteins and polysaccharides, with which they interact by hydrophobic and van der Walls forces and perhaps by ionic bonds. Various solvents or solvent combination have been suggested as extract ants, but most lipid analysts use chloroform-methanol as suggested by Fol ch er Al.The endogenous water in the tissue is a ternary component of the system. The extract is shaken and equilibration with one fourth its volume of a saline solution, when the mixture partitions into two layers, of which the lower is composed of chloroform-methanol-water in the proportions and contains virtually all of the lipids, while the upper phase consists of the same solvents in the proportions of respectively, and contains much of the non-lipid contaminants. It is not always recognized how important it is that the proportions of chloroform, methanol and water in the combined phases should be as close as possible to selective losses of lipids may occur. If carried out with the correct protocol, this method can give reliable results.To know more about go to
  Lipid

 

 

Edited October 20, 2011 by meercy