Pre-oxygenate water bottles for addition before pitching yeast?

I was just wondering, could I use a carbonation cap (air line ball lock to PET screw cap adapter) or even just a sandstone to oxygenate some small bottles of water so I can prepare several ahead of time and just dump one bottle into 5 gal of wort? I don't have an oxygen tank and haven't done the math to see if you could absorb enough oxygen into a small enough volume of water. Potential benefits I could see would be extreme convenience at pitching time and keeping the sandstone clean because it only touches water not wort.

I would think that you wouldnt be able to oxygenate a small amount of water enough to make a difference, and how would you do it without an oxygen tank? It would be much easier to oxygenate the full cooled wort with an aquarium pump and your airstone. Sanitize the stone and line in 180+ water for 10-15 minutes before and after use. Later on, get a stainless diffusion stone ($20-30) and an oxygen tank ($20-50 at a flea market), it makes a difference, and will be one of those things you wish you would of done much sooner.