What I want to do
see if we use gelatin caps as sample containers. They cost a few cents each, 100 for $5 at my local pharmacy. I picked up 25 each of sizes 4-00.
My attempt and results
The gel caps have a lensing effect because of the shape, it is more severe the bigger the gel cap. The smallest #4, which was only a little bigger than the laser beam was the easiest to make fluoresce. I filled them with olive oil for my tests.
I moved the slit to the outside of my conduit box so I could get my samples right up against it, and then made a little tube out of black aluminum foil to slide the gel caps in.
I also tried them sideways. Only the #4 worked sideways. by just holding it.
The two big curves fluorescing at 670nm are a glass jar (control) and the #4 gel cap. The other caps, probably from the lensing, didn't work as well. The #4 worked as well as a glass container with the laser aligned perfectly, very close to the glass and along the slit.
I also tried out one of the cuvettes Jeff sent me, but couldn't get the fluorescence to read at any angle.
Questions and next steps
The gel caps weren't too hard to fill, but I always got a little oil outside (I used a dropper). So its not super clean. They don't seem to leak though, however they are hard to label and easy to crush.
Why I'm interested.
at 5 cents they're cheap and work great and are easy to get. they don't need a big sample, but perhaps need a mixing container.