Sample prep for HPLC

[raghuveer]

Hi,

I have Agilent 1200 fitted with RID and Hi- Plex H column. I am going to analyze spent media containing organic acids (Acetic Acid and Lactic Acid). Spent media also has salts like NaCl (15g/L), MgCl2 (2g/L) and 20mg of KI and KBr. Can I inject the sample directly after centrifugation and filteration? Will these salts interfere with analysis or damage the column? If any sample pre-treatment is required to remove these salts then which technique will be the best to remove salts leaving organic acid in it with good recovery?
Sorry I asked too many questions.

Thanks for your help

[tom jupille]

That column is a cation exchanger in the hydrogen form. Under typical conditions (low-pH aqueous mobile phase), heavy metals will displace the hydrogen and be esentially irreversibly retained. Over time, this *will* damage the column. Sodium is strongly but not irreversibly retained. High levels of sodium will give very large, very wide, very late peaks that will appear essentially like massive drift problems.

Cl- is excluded and elutes at the beginning of the chromatogram (the "
total exclusion volume" of the column); at high levels it can interfere with early eluting peaks.

You can get rid of metals by doing SPE with a cation exchange resin in the hydrogen form. You can get rid of chloride and bromide by SPE with an cation exchange resin in the silver form. BioRad sells de-ashing cartridges that will do this in-line, but you do have to change them regularly.