Would passing only ultraviolet light trough a prism onto a 'fluorescent' painted target show if it is of the A, B, C type by the projected angle/deflection?

 

Yes. (But you would need to find a material for the prism that is transparent to those frequencies; I don't think normal glass is.)

 I think you'll only register uva.

On 5/8/2020 at 3:14 PM, Strange said:

Yes. (But you would need to find a material for the prism that is transparent to those frequencies; I don't think normal glass is.)

Would a diffraction grating work? I've long been interested in splitting sunlight into its UV and visible rays separately.

You have to ensure the target would respond differently to the different frequencies 

27 minutes ago, ScienceNostalgia101 said:

Would a diffraction grating work? I've long been interested in splitting sunlight into its UV and visible rays separately.

Yes, as long as the material passes UV

UV spectrophotometers used to use fused quartz prisms.

They used to use crystalline quartz prisms- which makes life interesting because quartz is chiral. They had to make the prism out of two pieces o quartz, one left handed and the other  right.
I think reflective diffraction gratings are common now.

 

7 hours ago, ScienceNostalgia101 said:

Would a diffraction grating work? I've long been interested in splitting sunlight into its UV and visible rays separately.

Yes, but you might need some sort of "order sorting filter"