Chromatography Forum

I wonder what the backpressure would be with ~10cm column (75um ID) packed with Waters' 1.7um sorbent. Have anybody used PROXEON nanoLC with custom column packed with 1.7um sorbent? The max pressure the system can withstand is 5000 psi. Are there any REAL advantages over 3um sorbent? The application is proteomics, so samples are mostly peptides.

thanks for any comments/suggestions
Serg

I wonder what the backpressure would be............

Serg,

The backpressure depends (apart from the particle size and column dimensions) on the flow-rate, as well as mobile phase composition and column temperature.
So, I don’t think you’ll be receiving any qualified answers to your question, unless you are willing to describe the conditions in greater detail. Besides, what are your goals – faster analysis, better resolution, higher plate count, higher sensitivity…..?

Best Regards

thanks for the suggestions:

the flow rate is around 200nL/min,
solvent A is 5% ACN in water plus some formic acid,
temperature is, let's say ~20C,
the goal is to see a) is possible (backpressure!) to use 1.7um packing with PROXEON pump, b) if it is in fact possible then I will check if there are any advantage in using custom-made capillary column packed with Waters' 1.7um C18 in proteomics study

something like that.

thanks
Serg

Serg,
After a lot of consideration I arrived to the following approximate result:
The parameters you have set for the existing column can be transformed to approx. 0.16 mL/min flow rate on a 2.1 x 100 mm Acquity column. So with this low temperature and this mobile phase, I would expect a backpressure of about 4000 psi if you made the column that you are considering.
I’ll have to emphasize though, that I am far from 100 % certain (maybe 60 – 70 % at the most). Maybe Uwe could convey far more certain figures. In fact I’m sure he is in this lucky position.
If I were you I’d go forward with the idea and see where it’ll bring me. Although the flow rate seems a bit slow for 1.7 µm particles, but not way too slow.
Hope more people will comment on this rather interesting topic.

Best Regards

I just plugged the numbers into my old copy of DryLab and I get about the same number as danko (3300 psi). The estimates from the software tend to be a bit on the low side because the calculation assumes monodisperse particles. Any of these estimates are +/- 20% , so my guess is that you would be on the ragged edge of feasibility.

Thanks everybody,

Serg