Problem with inertsil SP column

[aniket1706]

For one perticular molecule containing phosphorus, I am using INERTSIL SP column. The mobile phase contains tetrahexyl ammonium sulfate, ETDA, TEA, Phosphate buffer(pH=7.5) and ACN. The method is isocratic. But after few injections,the peaks become broad. There is no regeneration procedure available on the net. Can anyone help?

[tom jupille]

What you are seeing is consistent with garbage from your sample accumulating on the column. There is no "universal" regeneration procedure (and there is no guarantee that you can ever recover the column). In general, what you need to do is to reverse-flush your column with something that is a good solvent for whatever kind of garbage is there (obviously, that depends on the nature of the sample). Things to be watch out for:
- Make sure that any solvent change doesn't involve precipitation of buffer or miscibility problems.
- Disconnect the detector before flushing the column.
- If possible, flush the column in the reverse-flow direction (check with the vendor first !!).

Moving forward, you will need to either improve the sample cleanup or use a guard cartridge (and change it frequently).

There is also a chance that the problem is coming from contaminated mobile phase. It is possible to tell this apart from sample contamination, but the procedure requires some patience. There is a description on our web site here: http://www.lcresources.com/resources/TSWiz/hs390.htm