Handling EPR spin-probes, specifically how to dissolve 5-DSA?

I want to do some EPR tests with 5-DSA (or related spin probe) dissolved into different crude oils.


It had not sunk into me that $100 of 5-DSA was a tiny amount of a very sticky solid. It's proving hard to deploy in each test. Better would be if I could dissolve my 5-DSA into, say, known volume of toluene and then pipette a few mL of that toluene mixture into the oil sample.


But is toluene the right answer? I don't want to destroy the free radical. How do other researchers handle their spin-probes?


