Chromatography Forum

Hello,
Recently I saw a HPLC method for analysis of drug substance were wide bore Reverse phase columns were used for analysis (YMC A312 6.0x150mm column). Please let me know what is the application of such wide diameter columns in hplc seperation.
Thanking you
Santosh Gandhi

My guess is, the developer of the method didn’t have a smaller diameter column of this particular chemistry in the drawer.
Or maybe the intention was to acquire larger fractions for further work/analysis/characterization.
I personally will try to avoid larger than 4.6 mm columns in analysis context for many good reasons, but it would be a bit off topic to discus that matter on this thread.

Best Regards

Hello,
Thanks Mr.Dankyo for your reply. In your reply you have mentioned that there are some problems which may arise on using wide bore columns may I know what they are. Moreover I searched the YMC column catalogue for YMC A-312 6x150mm column but I did not find any mention about this column . I also want to know whether a 150x6mm column is comparable to 250x4.6mm column of same column chemistry because the total column volume of both dimensions are almost same.
Thank you
Santosh Gandhi

Hi again,

In your reply you have mentioned that there are some problems which may arise on using wide bore columns may I know what they are.

The greatest problem with wide bore columns in analytical context is as follows:
If everything else is normalized, using a wider bore column will result in compound/s eluting in a larger volume when compared to separation/elution on a smaller diameter column.
In my world/mind, compound eluting in a large volume means lower column efficiency.
Summarized: Large volume = more diluted band (peak) = low efficiency column.
Some people would argue that it is not caused by particle size differences or degree of stationary phase coverage etc. so it’s not efficiency issue. And that was the reason for me not to go into details. But since you asked……

Another downside with large diameter columns is, the need to pump more mobile phase through the column in order to achieve an optimal/reasonable mobile phase velocity - that matches the utilized particle size.

Third downside is, the need to load more sample in order to achieve a reasonable sensitivity (peak height) compared to the sensitivity obtained on a smaller diameter column.

Moreover I searched the YMC column catalogue for YMC A-312 6x150mm column but I did not find any mention about this column

Could it be a simple typo? Maybe the author meant to write 4.6 but only the “6â€