FishLove

Polyethylene glycol looks like it would be a good surfactant. But I don't believe I'll be allowed to use surfactants as these change the interactions of the chemical with living aquatic life membranes.. I have have applied a shaker for several hours to an approx 10mg DHA /liter deionized water; the emulsion appears stable after 24 hours, and even maintains its cloudy appearance after 48 hours. Some droplets mix well into the solution (with a microscope they appear on average a few microns in length) but I still observe some droplets of oil on the surface of the media. I suppose I will need to find the water accommodated fraction of the oil, but in regards to forming emulsions for testing, prospects look good. Perhaps I can enumerate droplet size, volume, density with microscopes or look at turbidity/light dispersion with a spectrophotometer. One last question though, 1. Would adding a simple organic solvent (e.g. methanol) increase the stability of the oil in water emulsion or decrease it? Thank you all.

Thank you all for your quick replies and comments, they are at least encouraging. The ultimate problem I have with making solutions is I must expose living algae to these fatty acids... and tox protocolos limit solvent usage to 0.1-1% of total volume,otherwise I would load up on the solvents/surfactants. Maybe food grade stabilizers, thickeners, or surfactants such as lecithin may be used, but these appear to be slightly toxic or may alter the toxicity of fatty acids anyways by coating the lipids. And I don't have a sonicator... some I am testing some food grade DHA with a shaker and intense stirring... I suppose what I am aiming at is increasing the energy of the droplets so that they may be dispersed as possible (I believe I can potentially quantify oil droplet density later with spectroscopy or haemocytometer) for at least 24 hours. Eventually the free energy of the droplets in the system will decrease and droplets will coalesce... and I can't fight physics.

Hello I am graduate student at a university working on a M.S. in environmental science. I am asking for advice on creating emulsions in water beakers with lipids (poly unsaturated fatty acids). I want to create emulsions with fatty acids like DHA (docosahexaenoic acid, 22:6(n-3)). Seeing as how they are not saturated they should have some solubility in water...at pH 8 it is predicted at around a few grams/liter. However when I dispense 20 to 10 mg into a 1 L of water lipid droplets/vesicles still form, even after shaking vigorously. So as of now I have little hope of dissolved monomers but I want to at least create a 'stable' emulsion, or micro/nanoemulsion, that will last at least 24 hours. What is the best method to emulsify a sparingly soluble nonpolar compound in predominantly water (polar) matrix? I can't use alot of solvent (limited to 0.1% by volume). I have researched some possible methods; 1. Sonication for long periods of time (hours) 2. Handling methods to prevent formation of micelles/vesicles/droplets of fatty acid oil (e.g. adding very minute amounts at a time while vortexing... this could affect precision of final concentration though) 3. Saponify the fatty acids (e.g. add fatty acids to a alkaline solution, giving all the fatty acids a polar RCOOH- charge, making them more miscible), vortex them, and gently neutralize the solution with acid, bringing the micelles back into formation but creating homogenous mixture of micelles? would this work? My final product has to be something with around 10 mg/L of fatty acid in around 8 pH hardwater. Thank you all for your advice,