SAX for bromide

[push]

Hi
I need to analyze bromide in water containing TriChloroBenzene residue. I use Parisil SAX (Whatman) column and KH2PO4 buffer as a mobile phase. Bromide is stronly interfered with the TCB residue. I am thinking to add an organic modifier to the mobile phase. Which column and mobile phase can you recommend?

[tom jupille]

That's a silica-based column, so solvent limitations are the same as those for any bonded-phase column. Adding either MeOH or ACN should make the TCB elute earlier. The other possibility is to change your buffer ionic strength. Increasing the salt concentration should make Br- elute earlier; decreasing it should make Br- elute later.