Aqueous normal phase HPLC?

[Rose]

I have come across a method which uses a silica column and a mobile phase of water (80%)/acetonitrile/TFA. I have never used water in normal phase HPLC in high volumes, I was under the impression that it wasn't a good idea. Can anyone refer me to a useful resource/website regarding this type of LC.

Thanks

[Supercritical]

exactly, what is the column desription?

[Kazimierz]

Dear Rose,

It is new idea in liquid chromatography. Please look for all with the acronym
"HILIC" - Hydrophilic Interaction LIquid Chromatography.

HILIC is dedicated for separation hydrophilic or zwitterion compunds.
www.waters.com or Atlantis Columns Waters 11/03 720000793US pp.8
or Atlantis Columns. Application Notebook Waters 720000472EN 0404 pp. 1

Columns: Agilent ZorbaxRx-SIL 3.5um, Waters Atlantis-HILIC 3um, SeQuant AB ZIC HILIC Silica 3.5um, LG Inertsil Silica 5 um, Brownlee Silica 5um.

Each Brand of native silica is diffrent because of purification and technology of the product.

Extremaly important is pH (<2-4), type of acid, column regeneration and
injection solvent (max 10%H2O in acetonitrile) or mobile phase (5%-50% H2O in acetonitrile). It is possible modify mobile phase with bufors or chaotropes.
NaCl (0.1%) - causes irreversaly lost efficiency of column by 50%.

[Rose]

Thank you for your replies, the advice on suitable operating parameters is very helpful.
The column used is a Waters Spherisorb Silica. I did not think that this column was designed for HILIC type use and appears to suffer from re-equilibation problems, do you think that a column specifically designed for HILIC would give better results?

[Kazimierz]

Dear Rose,

I had tryed on ganciclovir several years ago. Firstly I used non-aquaous methanolic phase with 0.1% HClO4 and Supelcosil Silica acc. to Prof. Flanagan. The column initially was excellent separated of ganciclovir and acyclovir IS, however, is quickly destroed after 1 month. In oryginal paper
is Spherisorb silica (>20 years ago).

For HILIC I spent many years without good results because of non properly selected brands of silica columns.

You have right, dedicated for HILIC work it is need special purificated and prepared silica, without metals especially, and some producents shiped such columns in adequate phase. Also, HILIC phase is producent-guaranted compatible with 100% H2O.

Sophistic HILIC columns (polymeric) are compatible even with the basic pH.

[tom jupille]

HILIC is a relatively new name (maybe ten years or so) for a technique that's actually been around for a long time. You can find lots of 25 year-old references to carbohydrate separations carried out on amino bonded phase columns with ACN/water mobile phases for which ACN is the weak solvent (i.e., it's normal-phase, not reversed-phase).

[Einar Ponten]

Well, I hardly believe that the last invention for HILIC has been seen. For a period the philosophy has been that you "use what you have", with the exception of Andrew Alpert phases.

We are more or less dedicated for R&D in this area and have designed both silica and polymeric columns for HILIC. We try to offer the best support you can find and enjoy your enquiry.

Please visit our website or contact our support directly <mailto: support@sequant.com>

[Uwe Neue]

Rose, please check if the mobile phase composition is correct, since most true HILIC applications work with a high acetonitrile content instead of a high water content.

Second, I have to contradict Kazimierz. For several reasons, the Spherisorb silica column has a higher stability in an aqueous medium than other columns used in HILIC. The primary reason is the lower pore volume and thus the higher density.

I would under all circumstances use a Spherisorb silica column for HILIC if the peak shape is OK.

Rose, you can contact me at my e-mail, and we can discuss the details of your previous experience with Spherisorb so that we can work out an improved lifetime.