Chromatography Forum

Hi,
Can Anyone Suggest me the Suitable CApillary Column for the Analysis of ChlorodifluoroAcetic Anhydride , ChlorodifluoroAcetic Acid, TrifluoroAcetic Acid, TrifluoroAcetate,.
I Have the DB-624 Column. and Tried it But due to Acedic Nature of Samples the Stationary Phase has degarded with the time.
I also tried it on DB FFAP Column but the Peak Shape is not so good.
I got the Analysis on Hp-5 Also but in this case the Separation in all four compounds were not found.

pls suggest me if any more suiatble GC column is availabe for acidic nature of samples with proper stability atleast 1000 samples can be analysed

You require a packed column.

Is this a viable option for you?

Rod

Chandresh K. Soni

I hope you realize that GC is not the preferred method of analysis for these free acid analytes.

TFA might not damage a porous polymer GC column but there is a silica GC capillary or there used to be from Chrompack? I think, that has no silicone phase, but is a porous silica particle glued phase. Will it endure? Who knows?

Any silicone phase containing GC column WILL degrade. A FFAP thick film, not thin film, for capacity issues (as you noted peak shape is not best due to overloading the capacity which is low for a free acid) or a SP-1000 thick film is probably your other capillary choice.

I hope you pursue other methods than GC for your analysis.

best wishes,

Rod

Thanks ROD for your Valuable Suggestion.
But I got the Better Peak Shape and Also the Separation in All the Components on J&W Capillary Column eith the Stationary Phase of Trifluoropropyl mixture.
I know this is not so much longer stable column but it will help me to solve the analytical Issues which are rising due to DB-624 Capillary column.
I also hope that the analysis is right b'use the CDFA peaks is more better.

againe thanks all the team for valuable suggestion.

regards
Dr.Chandresh k.soni

The trifluoropropyl silicone phase is probably the closest silicone phase to the Krytox 143C phase in selectivity.
This phase coated on a Carbon support is probably the best for the anhydride component, but may not be the best for the free acids. You will have a limited and possibly variable performance from the capillary you have chosen but hopefully it will be adequate to your needs for a short time. (a lot less than 1000 injections)

Good luck with your research.

Rod

Thanks ROD,
My Aim is to check the Acid Impurity in Anhydride, I know if acid content is higher then this stationary phase is degraded but it may be suitable to check the acid content in an hydride.
i also want to know at present we are using the Nitrogen as well as Hydrogen but during hydrogen we get some peaks in higher temprature which was not shown in the case of nitrogen.
my doubt is also on carrier gas is the Hydrogen is suitable on this type of compound and on this column.
regards
Dr.Chandresh k.Soni