Iron contamination

[laurimc]

Hi all,
I injected a sample that (apparently) had too much iron in it and contaminated my system. I've cleaned up the column and supressor now, but I'm wondering: how much iron can I have in a sample and still be safe to inject? My samples are about 20-30ppm iron, but I want to dilute as little as possible so I can still see the anions.

FYI:
Dionex ICS-2100
AS-18 column & guard
ASRS 300 supressor
CRD-200 carbonate removal
1mL/min 12mM-52mM KOH

Ideas?

[H2Oh]

Do you care at all about phosphate?

[Markus Laeubli, Metrohm]

I assume that if you have that much of iron, you will not find any phosphate.

[laurimc]

H2Oh, I really don't care about phosphate.

I've also tried using the OnGuard II H cartridge but it doesn't seem to help, so I'm stuck with minimum 50x dilution.

Anyone?

[DJ]

SCX or else mixed bed guard?