Chromatography Forum

Hi everyone!

I'm looking for the specifications for the USP G27 and G35 phases.
I already know the name of the phase, but I'm not shure of the column length, ID and particle size.
I'd also like to know the variations accepted for Length and particle size (I guess the length is +/- 70 % but I'm not sure) in the USP.

Thank you very much in advance!

Vincent

Vincent,

The phase descriptions of G27 and G35 have nothing to do with particle size, but the chemistry of the liquid phase used to make packed and capillary GC columns.

You are looking for a description of a packed column as far as I can tell. A packed column has length, ID, and a support which has a size distribution which is then coated with a liquid phase such as G27 or G35 on a weight percentage basis.

Please restate your question more exactly and the Forum members would be glad to assist you.

best wishes,

Rod

Page 33 of the Phenomenex catalog ('02/'03) has the USP phases and Phenomenex suggested replacement.

The G27 is a DB-5 type column. and the G35 is a free fatty acid column (FFAP).

I think this is the type of relation you are looking for?

Vincent,

The phase descriptions of G27 and G35 have nothing to do with particle size, but the chemistry of the liquid phase used to make packed and capillary GC columns.

You are looking for a description of a packed column as far as I can tell. A packed column has length, ID, and a support which has a size distribution which is then coated with a liquid phase such as G27 or G35 on a weight percentage basis.

Please restate your question more exactly and the Forum members would be glad to assist you.

best wishes,

Rod

Excuse me I made a mistake.
I was speaking of the liquid layer size ( I think its also written Df??) and not of particle size.

To sum up, I'd like to know if my columns could be used according to G32 and 27, even if they have the same phase composition but not the same length, and liquid layer size.
For example, could my VARIAN CP-sil 8 CB 10m*0.53mm*2µm be used as USB G27 phase composition.
I know that variations are allowed in USB for Length, ID, and Df but I don't know the values.

I hope this is more clear.
Thank you so much

I believe that the USP does not have an unique column dimension specification for any phase description. That includes film thickness, Df.

An unique column may be described for a monograph however.

As long as your test does not mandate a specific column (for example the residual solvent test <467> does specify the length, ID, and film thickness as well as the phase itself) then any similar column should be allowed as long as the column used is capable of performing the separation the test requires.

But as always, ask the USP directly for the correct answer to any specific question you may have.

best wishes,

Rod