Hallo

I am about to start working with a method which involves dioctyl sulfosuccinate sodium salt (cas# 577-11-7)in the mobile phase. Since i have never worked with such MF i would like to know if there are any precautions i should take.
Hints gladly apprieciated, thanks in advance.

This is an interesting compund and I assume this compound does not behave as an Ion Pairing Reagent but as a detergent in your mobile phase like SDS. This is my assumption but I may be totally wrong!!!!. If your analyte is some kind of multimeric peptides/proteins and your method is SEC, this explains why you need it in the MP and it might act as a dissociation agent??Do you have acetonitrile in your MP?I am sure others will comment on this assumption. Sorry for not being very helpful!

Ananda S.

I have used dioctyl sulfosuccinate (DOSS) often in the past as an ion pairing reagent in the mobile phase. It may be unusual to handle the solid material. If purchased as a fluffy light solid, then tear off pieces with your gloved hands to weigh out. If purchased as solid chunks, break off pieces to weigh out.
I would recommend pre-mixing the mobile phase when using DOSS. Flush the mobile phase solvent line with the same solvent composition as your mobile phase minus the DOSS, any buffers, and other additives before loading your mobile phase. Program from your storage solvent to the mobile phase solvent composition without any additives, then switch to your mobile phase. For example, if your mobile phase is 35:65 acetonitrile:water with 4 mM DOSS, 0.3% DEA and 1% acetic acid, program to 35:65 acetonitrile:water, then switch to the premixed mobile phase and pump for ~ 30 minutes to equilibrate. After your run, flush with the mobile phase solvent composition minus any additives to clean, then program to your storage solvent. As with other ion-pair reagents, the column you select should only be used with DOSS-containing mobile phases. Other separations would be affected by residual DOSS on the column.
The main thing is to be sure you flush with your mobile phase solvent (without any additives) to clean out the DOSS from your HPLC and column. I think that you will find the separations to be very good with the DOSS.

Thank you for your postings.

Ananda - I will be useing DOSS as an ion pairing reagent (my sample is a simple pharmaceutical product not biological)

Anonymous - this are the informations I was looking for, so far I have been working only with conventional RP-HPLC and I want to be prepered for possible surpraises

Thanks again

Why work with ion pairing agents at all... there are columns that will separate polar compounds without the need for these agents.