[Legolasas5]

Hello,
I am trying to come up with a method for non-ionic detergent, such as Hecameg or Tween 20, removal from water samples prior to HPIC analysis. Detergents are not compatible with HPIC system and precipitates in PEEK tubing and conductivity suppressor. Because of that we are experiencing loss of resolution and peak tailing. And that doesn't help us run quantitative analyses. 
Dialysis isn't an option because of small sample sample volumes (200-1000 μL).
So I was wondering, can someone suggest articles, ideas or already existing methods to improve my sample prep. 

Thank you
 

[Arkcon]

Ethyl acetate extraction is one method suggested for analytical peptide samples: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2852680/

Although, you can go ahead and look up other solvents selective for detergents and not affecting your analyte.  You can also tell us the analyte, so we don't make suggestions that are useless to you.

Thermo-Fisher sells a number of spin columns for this task, and has examples of the analytical benefits using their spin columns provide: https://www.thermofisher.com/us/en/home/life-science/protein-biology/protein-mass-spectrometry-analysis/sample-prep-mass-spectrometry/detergent-removal-peptides.html

You might even try this on-line with a RP guard column. As in here: https://www.sciencedirect.com/science/article/pii/S0378434796002137

It this is a quantitative analytical procedure, you may have to re-validate after you find a solution.

[Legolasas5]

Quantitative determination of magnesium ions is most important for us.
Also, I forgot to mention that we have already done some experiments with Pierce^TM Detergent Removal Spin Columns but observed 30-40% of analyte loss.

[Babcock_Hall]

There is such a thing as micro-dialysis, and it is done in a very small chamber, and it is sometimes used in protein crystallography (see first link).  However, there has to be sufficient size difference among the chemical species to make it practical.a  https://www.hamptonresearch.com/documents/growth_101/7.pdf   There are also Zip Tips (see second link), but I don't know how similar or different they are from what Pierce sells (the product that you mentioned):  http://www.emdmillipore.com/US/en/product/ZipTip-Pipette-Tips,MM_NF-C5737  I suppose one could bind the Mg(II) ions to a small sample of an ion-exchange resin while the non-ionic detergent flows through, but then one would have the problem of how to elute the Mg(II) ions.

[Legolasas5]

Another idea has crossed my mind. Would it be possible to capture all unbound detergents from aqueous solutions by using some hydrophobic protein, that is insoluble in aqueous solutions. Protein would solubilize as detergents bind it. Then after using some protein removal spin columns solution would be detergent-free (at least I hope so). Would this approach be fruitful?

[Babcock_Hall]

I don't consider myself to be an expert on removal of detergent.  On the one hand, you could immobilize a preparation of bovine albumin that has been made free of fatty acids.  Bovine albumin can bind about six equivalents of phenol red, for example.  On the other, I don't see an obvious benefit to that method versus capturing the detergent by using a method based on C-18 or other hydrophobic matrices.