Chromatography Forum

Hi,

we have some HPLC's and UPLC's running in our lab, but we would like to move to UPLC in the future.

When we are using USP methods for our raw materials, we may adjust our column length for 70%, column diameter for 25%, particle size for 50% and flow rate also 50%.

Suppose we have an HPLC method:
column: 250 mm x 4.6 ID, 10µm particles.

with some mathematics, you can find that an 100mm x 2.1mm 1.7µm particles will get an equal, or even better separation.

We found some references here:
http://www.usp.org/pdf/EN/USPNF/PF35(6)_Stim3.pdf

Are such adjustments (already) allowed?
Or can this be justified otherwise?


Ace

You will get the equivalent separation by changing column length and particle size in proportion, which would mean that you go from a 250 mm 10 micron column to a 50 mm 1.7 micron column.

A stimulus article is not yet the final word, although the response from people to this suggestion was generally very positive, and an implementation of the ideas in this stimulus article is very likely.

If I were to implement this change in my lab, I would proceed with the necessary tests (and potentially a business case) and hope for a speedy implementation of the suggested changes in USP. Even if the suggested changes are not accepted/implemented in the near future, one can allays conduct and document an equivalence study, which in turn should justify the utilization of a superior method/technology.

Best Regards