HILIC column storage

[thohry]

Hi all,

Have you got any idea about storing Hilic column? I mean what solvent/solvent mix to be kept inside the column for extended time.

Thanks

[Noser222]

Acetonitrile is usually fine.

[rhaefe]

Ad the manual that comes with the column is usually a good source of information like that.


--
Robert Haefele

[Jade.Barker]

I agree with checking the column documents. I have a different column than you, but my paperwork recomended 2 different options.

[mohan_2008]

It is hard to find the column purchase paperwork that describes the column storage - For Hilic columns. For Reversed phase, each manufacturer gives a very good recommendation about storage but not for Hilic columns.

Hilic operates on a different mechanism as opposed to traditional RP.
We usually store it in highly organic solutions, such as 90% ACN and 10% Water.

[Patrik Appelblad]

The Merck SeQuant recommendation is to store ZIC-HILIC columns, as shipped, i.e. Acetonitrile / NH4Ac 5 mM, pH 6.8; 80:20 (v/v).

This and other useful HILIC related information can be found at

http://www.sequant.com/download and
http://www.sequant.com/FAQ

Also, one can order free of charge, "The Practical Guide to HILIC".

Another point to bear in mind...

One should remember that long term storage of columns in high portions of organic solvent may lead to depletion of ions from stainless steel (column tube and frits).

This is one of the reasons to why ZIC-HILIC columns are packed in PEEK hardware. Another reason is the biocompatibility.

[Victor]

Patrik,

Why would long term storage of a steel column in pure ACN lead to depletion of metal ions? I would have thought storage in any sort of aqueous solution eg ACN-ammonium acetate would be more likely to dissolve metal ions than pure ACN? (Of course you do not have this problem if you use PEEK columns).

[Patrik Appelblad]

Victor,

I know a few studies (unfortunately none is published) where this has been experimentally verified. Maybe I have opened a "can of worms", and that was by no means the intention.

As this is a scientific forum, I only intended to share some acquired knowledge especially as this technique is still rather new to many, and due to the topic on storage of HILIC columns.

In the previous posts, recommended storage solutions are not pure ACN, rather aqueous ACN solutions, but I know that some manufacturers also recommend 100% ACN as long term storage solutions.

Additionally, if you store a column in 100% ACN, I would tend to believe it would take a substantial amount of time (column volumes) to equilibrate the column for proper use in HILIC.

I will try to see if I can find data to post at a later stage.
Perhaps there are others on the forum that may contribute to this post.

[HW Mueller]

There is actually someone that claims that pure anhydrous organic solvents are more corrosive to stainless steel than organic water mixtures? Patrik, maybe you can close this can of worms by carefully reviewing this unpublished whatever again and reporting some details here?

[Patrik Appelblad]

In my orginal post I wrote:

One should remember that long term storage of columns in high portions of organic solvent may lead to depletion of ions from stainless steel (column tube and frits).

I did not claim that pure anhydrous organic solvents are more corrosive to stainless steel than organic water mixtures? Hans, if that is yours and others interpretation of the previous posts, I guess my English is not good enough. Sorry!

My intention was only to draw peoples attention to the problem with storing stainless steel HILIC columns in [b]high portions of organic solvent[/b], and the problems associated with it, especially as ions do have retention in HILIC mode, and they will accumulate on the stationary phase, hence possibly altering the selectivity...if they are not eluted form the column.

[HW Mueller]

Normally one would think that the higher the organic %, the lower the corrosion. One can think of an exception: If you have some active substances in there, like an acid or base, in addition to the water and organic. Some of these can be very agressive if not "neutralized" by too much H2O.

[Victor]

Thanks for these comments Patrik and Hans.

Patrik-you still seem to suggest that there is something more corrosive about high concentrations of organic solvent, in combination with buffers. This seems to imply that high concentrations of organic solvent in combination with buffers are somehow more corrosive than low concentrations of organic solvent in combination with buffers? Can you explain this? Of course, I could not see why anyone would want to store a HILIC column in a low concentration of organic solvent....

Personally, for long term storage, I would use pure ACN, even if it took longer to equilibrate with the mobile phase. In any silica based column there must be some possibility of hydrolysis of the bonded ligands or even the silica itself-especially at a pH of 7 or above. This would be avoided by storage in pure ACN. I think at least some ZIC-HILIC columns are silica based, although I do not know what proportion of your sales are the polymeric version.

[Victor]

Sorry Hans- I missed your last post while writing mine. I entirely agree with you that I would guess corrosion would be LESS of a problem with HILIC mobile phases which are rich in ACN.

[Jade.Barker]

For Reversed phase, each manufacturer gives a very good recommendation...

Our Ion Exclusion Columns do come with paperwork too.