Base-Deactivated End-Capped Column

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

19 posts Page 1 of 2
Dear Members,
I have got a pharmacopeial method that used base-deactivated end-capped C18 column. Could everyone give me list of the columns and manufactures those met the specification?

Best regards,
SYX

Macherey-Nagel's full line of Nucleodur columns meets those specs. The columns GRAVITY, PYRAMID, and SPHINX are designed to be base deactivated and are end capped. Additional, all are scalable. Need info e-mail us

sales-us@mn-net.com
Dear syx,

most modern C18-phases are so called base deactivated columns. I suggest to contact some well known and reliable HPLC column suppliers.

e.g. www.phenomenex.com (Luna C18(2), Synergi HydroRP)
Here you can also request a USP guide and a USP phases poster

Steve, what are base-deactivated columns? Would you care to explain?
Uwe,

Forgetting things again, ruff time at work or did you forget to take you medicine again?

Let’s see, our next Macherey-Nagel seminar is at Merck and I think I can get you in. You can be assured that unlike a Water’s Seminars we will not take your literature away and ask you to leave. And I am most confident that you will learn from Dr. Rieger.

I will answer your question with the same cynicism as you have asked it and I will type slowly for you just in case you have forgotten. B a s e d e a c t i v a t i o n S ilica

First - Get a column and a beaker of base (Lewis bases are NOT acceptable).
Second - Put on Ruby shoes.
Third - Clink column to beaker three times repeating “There’s no columns like Watersâ€

I think I have got a headache now ... :?

Mr. Steve, could you please answer Mr. Neue's questions with simple words?
I really want to know the explanation about base-deactivation.

Same here

Base diactivated columns are columns with reduced silanol activity/plar interactions towards bases (amine, amidines, etc.) which have tendency. This is achieved by end capping or other means. Just do a search on Google with key words base+deactivated+columns.

“Base deactivated stationary phases generally provide better peak shape, increased column efficiency, and improved lot-to-lot reproducibility when separating polar compounds. They have been particularly useful in improving the separation of samples containing basic compounds. However, there are occasions when typical base deactivated phases lack adequate selectivity.
Manufacturers of base deactivated columns try to minimize polar-polar interactions between analytes and the stationary phase. Because of this, most base deactivated columns have similar selectivity for polar compounds. This means that if one brand of base deactivated column lacks selectivity to adequately separate a pair of polar solutes, other brands of base deactivated columns will also probably lack adequate selectivity for these solutes.
Stationary phases that permit polar-polar interaction through silanol activity offer alternate selectivity to base deactivated phases, but it often comes at a cost of poor peak shape and uncertain reproducibility. The ProntoSIL C18 EPS solves this problem by providing both enhanced polar selectivity and excellent peak shape (Figure 1).â€

Hello SIELC_Tech,

I hope you don't mind if I add a few things regarding base deactivated silica.

First generation HPLC base silica have had a high content of metal impurities and these impurities lead to an increased acidity of the residual silanols. These lead to peak tailing, chelatisation and other things which may compromise a RP separation. Base deactivating was first a kind of chemical cleaning procedure ("wash") of the base silica bofore making the bonding process. This procedure help to reduce the metal content of the silica surface and so reducing the acidity. Modern base silica are manufactured from ultra-pure reagents and start with much lower metal contents. Thats the reason why most modern phases, like all above mentioned will meet the requirements of a USP base deactivated phase. Older base deactivated phases carry sometimes a BD or BDS in their names.

Dirk

This is achieved by end capping or other means


If it is achieved by end capping, why the pharmacopoeia said: base-deactivated end-capped ... sound like they are different.

However, thanks for the explanations. Feel like analgesic. :wink:

Dirk, I would agree with your explanation, especialy as there source is a pharmacopeial method, which is somewhat older.
There has been some confusion on base deactivated columns: some use specially prepared or treated silica, others use special phases.

Syx, I would try to get column with BD or BDS in its name.

Steve, maybe I am wrong, but at least in the german MN catalogue _NO_ Nucleodur column is labelled "base deactivated". Some Nucleosil phases are.
I think thats why Uwe wanted your definition of base deactivated.

The procedures and chemicals used in base deactivation are tightly held secrets for the manufactures. Due to steric reasons 100% base deactivation can not be achieved

base deactivation = end capping

I can not read Uwe mind

All Nucleodur columns are base deactivation along with some Nucleosil columns.

If you see Uwe today tell him to have a good day.

We've had very good luck using the Phenomenex Synergi RP-Max column. It's a base-deactivated, end-capped column, but it's a C12, I believe, rather than a C18. Don't know if that will disqualify it for you, but it's worked well for us.

FWIW,

mike

Alex Buske

Macherey-Nagel web page

https://www.mn-net.com/web/MN-WEB-HPLCK ... amesE?Open

show all of the Nucleodur columns are base deactivated. Maybe you have an old German catalog.

So, if I read this correctly, "base-deactivated" means the same as endcapping. Now, endcapping can be measured. It is a verifiable procedure on any packing. We also need to realize that all modern packings (with the exception of some of those that are used as water wettable or AQ packings) are endcapped.
To use "base-deactivated" together with endcapping is marketing doublespeak. It means nothing.
Of course, the correct use of the English language would indicate that "base-deactivated" translates into "deactivation by a base". It does not mean "deactivation so that it does not interact with a base".
Which goes back to my original question which was intended to demonstrate that "base-deactivated" means nothing - nada - nil - rien - gar nichts...
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