[Delta876]

I'm a high school junior doing some biochemical research at a local university. I've just started a project in which I will be testing to see if pentabromodiphenyl ether is an endocrine disruptor. To start off I need to create a stock solution but this is where the problem arises. Penta-BDE is lipophilic and I've found literature that reports it being soluble in many common food lipids and other non-polar organic solvents. I've tried to dissolve it in olive oil and it didn't dissolve. I thought I might be over saturating it so I reduced the amount of Penta-BDE and it still didn't work. It always forms a suspension. I know it dissolves in most hydrocarbons but the solvent can't be toxic as most of them are. The biochemist that is helping me had a few suggestions but none of them worked. Does anyone have any other suggestions or solutions?     

[sondakem]

You didn't indicate what concentration you were aiming for.  I believe it will have to be quite low even in ethanol.  You may need something like PEG or other micellular forming surfactant to help solubilize it if you are limited to aqueous or aqueous/alcoholic solution.

PBDE is soluble in solvents that are toxic by themselves; on a mole per mole availabilty basis the solvents are probably more toxic.

[Delta876]

137 microg/kg was the initial dosage.

We tried making a solution with 1g PBDE in 25ml of oil (0.04g PBDE per 1ml) and even then it seemed to be oversaturated. I've found other people who have used far greater concentrations than what I'm using and it worked out fine. PEG was one of my first ideas but I wanted to try a lipid first as we need a solvent that is digestible. 

[sondakem]

I must be slipping.

PBDPE is usually a mixture of isomers and congeners.  The higher congeners are less soluble than the PBDPE.  This may impact on any conclusions you come to.

isomers=different arrangement of Br on the rings
Congener=different number of Br in the molecule; tetraBDPE, hexaBDPE etc.

If you are using a commercial fire retardant you may have to purify your material or you may want to obtain pure material.