Efficient polymer based HPLC columns for high pH?

[mbreslav]

Which non-silica gel polymer column have good efficiency for small molecules separation? (there are indications that my XBridge is not stable enough).

[HPLC chemist]

It depends on your molecule of interest and your sample matrix. I would check out the Tosoh website. What are you trying to do?

[mattmullaney]

Hi mbreslav,

Also, Zirchrom

https://www.zirchrom.com/

Supelco

https://www.sigmaaldrich.com/analytical ... ge=9659234

or porous graphitic carbon.

https://www.thermofisher.com/order/cata ... 003-031030

Depends strongly on what you're working with. Zirconia/Titania have peculiarities in handling, as does porous graphitic carbon.

[mbreslav]

I will have to try. I am separating common actives and impurities in the multi- active cold medicine formulation.

[mattmullaney]

Best wishes. I tried out Zirchrom phases in my past (DiamondBond and PBD) as well as porous graphitic carbon. These phases "like" THF and phosphate for bases as well as high temperatures...please be warned:

https://www.zirchrom.com/pdf/RPMDG.pdf

I ran at 60 - 90 degrees with no ill effects.

Hypercatb worked well with underivatized amino acids.

[Multidimensional]

You requested "have good efficiency for small molecules separation?"

None of the above suggestions provided would be considered efficient. The carbon and Zirchrom phases are some of the worst. All have poor loading and very poor efficiencies in general when compared to all types of silica supports. You might want to consider some of the hybrid silica columns. Better yet, can you tell us specifically which compounds you are dealing with? That sure would make it easier to provide suggestions.

[mattmullaney]

Hi again, mbreslav,

Here are other possibilities for a phase that can be used under alkaline conditions:

https://www.hamiltoncompany.com/product ... gs/prp-c18

and another:

https://www.emdmillipore.com/US/en/prod ... R3.Lxi,nav

and one more:

https://www.sigmaaldrich.com/analytical ... gh-ph.html

I've not used any of these phases myself. Best wishes in your search for an appropriate material for your application(s)!

[mbreslav]

Thank you!

[HPLC chemist]

Why are you having so much trouble? I performed cough cold APIs (Acetaminophen, Pseudoephedrine, Guafenison...) using pH 3 phosphate buffer and Acetonitrile. Why such an alkaline pH?