Egg Yolk Coacervates & pH Imaging

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Egg Yolk Coacervates & pH Imaging

Post by GaryGaulin » Tue Mar 03, 2009 3:02 pm

I'm trying to describe a new (for teachers) classroom experiment where egg yolk is mixed with red cabbage pH indicator solution which forms very lively (what should be) coacervates. My first problem is I do not have the microscope system to get a good video of them but here they are at around 1600x shown next to large bubble in upper left zooming out to show some 3D.

I now have a very blue halogen auto headlamp under an older Swift microscope with mirror removed to adjustable lens/iris through stage then AO 40x darkfield objective straight to 40x camcorder with zoom up full with light on microscope up until camcorder iris starts closing which seems to help get sharp colors but too bright they seem to get overwhelmed by background color coming from the lightsource. I could get a 100x objective cheaply enough (about $40) and have a condenser lens that gets the light in a good shaped cone to send up and a few precision photographic enlarger lenses of three strengths with irises on each to further change how the slide is lit from below. But I'm not sure whether I'm just wasting my time or there is something I can do that will make a microscope that would be comparable to what goes for almost $1000 on ebay because of phase contrast being added. I also have research diffraction grating and front surface mirror lenses to eliminate going through glass even. If it's possible to way outdo the $220 dollar 1600x without phase contrast then I would want to do that but I'm not sure whether that would really add much. Thought I should ask what microscope experts who I hope are here what you think I should do. Or what you would do with no more than $220 (less better) and a good junk pile of optics.

Chemically, the pH of a coacervate should be determinable by color. That seems to work. Since the only bright yellow is the egg yolk coacervates that picked up very little pigment would be the yellow ones. Those that are red to blue then green would have enough pigment to register a valid pH value. That part is relatively straightforward.

Where things get complicated is in explaining the movement. I think I see the pH indicator outside the vesicles changing color to what looks like ion or proton propulsion. Or it could be just that I have junk for a setup and am seeing something not actually there. In either case, I'm seeing these very solid egg yolk filled vesicles bouncing off each other in a pH indicator and have to figure out what is going on but after days of looking there was no answer found. So I'm not sure where to begin with this rather sizable science problem I have to figure out. Any ideas appreciated.

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