Fluorine impurity

[km06]

Hi All,

We are getting an impurity by F-NMR, which is not seen by HPLC or LCMS. As we have to quantify this, can anyone suggest which technique will help. It may be inorganic also.

Thanks

[cyork]

A fluorine ISE can determine fluorine concentration in aqueous solutions. It's finicky and there are a lot of interferences. You need to generate a standard curve to calibrate the electrode (we used NaF solutions for standards.) The inorganic sample was mixed with a mixture of sodium and potassium carbonate in a ceramic crucible, put in a muffle furnace up to 900C. The carbonate fusion product of this reaction was water soluble. We were testing at the 50% weight level though, if this is at typical impurity levels this may not be feasible.