Derivatizationproblem

[sankie]

Dear Friends,
I have a problem with derivatization for metformin for impurity F.

I have to derivatize metformin for the quantification of impurity F using flourodinitrobenzene.

I am getting a peak on the same RT specified for impurity F. but i am not getting any peaks in metformin area which is given in the pharmacopoeia.

In Pharmaocopoeia, they specified that to take 1ml of flourodinitrobenzene and make up to 100ml with acetonitrile. but the material is solid which has melting point around 29C. what I have to do? do I have to melt the material to room temperature or do i have to make it to a solution using propylene glycol (to which it is soluble).

Propylene glycol makes any problem with C18 colume?

Please help me.

Thanks

[MSCHemist]

It is pretty viscous but shouldn't really be an issue. It is pretty polar and should wash right out of a C18 column in Reverse Phase though it may coelute with your compounds of interest. I run samples of flavors in propylene glycol on the GC and get obnoxious blob peaks 7 minutes long in the middle of my chromatogram. What detector are you using?