Question

After a Melting point determination, why can't you re-use the solidified substance and capllary tube for subsequent determination?

Answer 1

In reality you probably could, however it is not good science as it has been considered to be contamined or already used and a new substance or solution should be obtained. I know this is wasteful but, that is just how it is.

Answer 2

I don't think it is all that wasteful. Those tiny capillary tubes are IMPOSSIBLE to clean. Even if they could be cleaned who would trust them? You're right. Get a new one.

Answer 3

It is better to get a new one as the used capillary would have residue of the other sample and the residue would act as an impurity causing an alteration in the end product