Sodium metabisulfite, sulfite and sulfate

[bunnahabhain]

Hi everyone

I'm looking for a method to determine sulfite and sulfate as impurities in sodium metabisulfite. I have found a method using ECD in sodium carbonate buffer, but we don't have an ECD here. I thought about our new ELSD, but of course this won't work with sodium carbonate. Any other ideaif I can get those in an ELSD compatible solvent system?

Thanks,
Jörg

[Hollow]

I would adress this problem by IC rather than HPLC.

Maybe it can be seen also in the low UV region or by RI, but sensitivity is probably not enough