I am writing in my research on the free-radical scavenging activity of various flavylium compounds. I may need to have DPPH shipped as a result of a lack of supply; I am just wondering what sort of precautions I might have to take and how viable it is to do so.
I understand that DPPH solutions need to be stored very well, but I'm assuming DPPH is most likely shipped in its powder form. What I'm wondering is what its stability as a whole is in solid form. Should it be constantly kept in darkness so as to prevent photooxidation and kept in a cold place, i.e. a freezer?
Even so, how long would its shelf life be by then, and how long would it be without taking precautions and leaving it at room temperature and normal lighting?
I'm asking so as to prevent or minimise the loss of its free-radical status.