Removing SDS from a Waters BEH C18, 50 x 2.1mm, 1.7µm Column

[JenLincoln]

Hi,

I have a column that is heavily used with ~20mM SDS at 75ºC with a pre-filter (Run-times of 16hours daily – yes I know that’s not very good!). I have tried using many different wash procedures to clean the column (100% ACN overnight/ Water:MeOH 50:50/ Water:ACN 95:5/100% MeOH) as suggested in the method but I still have a very poor baseline and poor integration of my component peaks. Is there any kind of wash procedure of chemical that I could use to deep clean my column to prolong my column shelf-life and maintain a good baseline?

Thanks in advance.

[JMB]

Jen,

This topic was raised by me and discussed about 8 yrs ago.

Search either posts by JMB and go to the 03-Aug-05 post or search the topic of "Removal of sodium dodecyl sulfonate from a C18 column".

You will find several suggestions.

Please let us know what works in your case.

[mattmullaney]

Hi Jen,

Only thing I know is that I really don't much like SDS...seems that for needle/seal wash methanol and ethanaol mixtures with water are helpful, and that for sure MeOH is a better solvent for SDS than either THF or ACN.

My suggestion: try MeOH as a first means of removing SDS. See what happens, and good luck.

[HPLCaddict]

As already said, there have been several discussions in the past about how to remove SDS. Several washing procedures have been suggested, but what it boils down to in the end is: You can never be sure if you've managed to remove all of the SDS. Even small amounts remaining may considerably alter the selectivity of your column, depending on the analytes. Therefore, the old lore of ion-pairing HPLC still holds true: If you've used a column for ion-pairing, dedicate it to that method. If you want to run a non-ion-pairing method, use a column that's never seen any IP reagent.

[JenLincoln]

Thanks everyone - I will try a wash with MeOH:Water and also check out other posts created before.

I always dedicate columns to methods but I am running this certain method alot and don't want to keep buying columns...

[mattmullaney]

Hi JenLincoln,

HPLCAddict has a good point...was hard enough for me to find MeOH mixture(s) for good needle/seal wash solutions...I'll admit I didn't try these to remove SDS completely from HPLC columns.

Apologizing for an off-topic...I've also seen ion-pairing agents used in gradient methods...from Compendia!! Also kind of a taboo thing to do, only asks for troubles in the long run.

[Vlad Orlovsky]

the alternative to washing off IP reagent is to use mixed-mode column where IP reagent is attached to the surface . There are several manufacturers besides us who are producing all type of mixed-mode columns. You can use mixed-mode column with any type of gradinet (single, double and triple) without having any issues. Columns are compatibel with 100% ACN and 100% of water.