Column for SDS

[MT]

I am currently working on a formulation that contains some sodium dodecyl sulfate. I wanted to analyse the drug content in the formulation using HPLC. However I was told that SDS based formulations can negatively affect the column (not too sure how) reducing the column's lifetime. Hence I was wondering if anyone else had used an SDS based formulation in HPLC and how they tested it? i.e. is there a particular column type that needs to be used.

[chromatographer1]

Some of the SDS can stick permanently to the column and then you no longer have a reversed phase column but a ion exchange column with sulfate ion as the active moiety.

Not good when you want a nice neutral column that doesn't cause tailing with bases.

Get the idea?

best wishes,

Rodney George
consultant USA

[HW Mueller]

Rodney, what do you mean with "stick permanently"? Enough sticks to influence the chromatography during consecutive injection of sample, or that one can not get rid of it once injected?
I have used LiDS to clean Pinckerton and I think Inertsil columns, no changes that I could attribute to the LiDS.

[chromatographer1]

It depends upon the nature of the silica used and the possible inadequate means used of 'cleaning' off the soap (SDS), Hans. Soap CAN leave a 'film', a residue which can be difficult to remove if the proper means are not utilized.

To answer your question, I suppose varying the amount of SDS in injected samples can make the retention characteristics of the column variable. I was addressing the situation of using the column for a non-SDS containing sample after using it for a sample containing SDS.

Ion-pairing reagents have been known to change the selectivity of columns in an inconsistent manner from column to column. I suppose modern columns may be affected less by these reagents and SDS than those used in the past.

Rodney George

[Bryan Evans]

Both posts are correct:

- With a lot of flushing, you can probably clean the (IP) from the column so
that it's back to normal, but...
- Best practice is to just dedicate that the 'IP column' for assays that use the same IP.

SDS is used a lot as a media for dissolution assays. The mobile phase I've always seen consists of 0.1% H3PO4 / organic.
I was told the 0.1% H3PO4 prevents the SDS from forming micelles (no clue if that's true).

Try a google for 'sds dissolution hplc' - it brought up some interesting links

[Consumer Products Guy]

Most of our samples contain sodium dodecyl sulfate and its ethoxylates, we inject samples with those all the time on RP18 columns, when we assay for other components.