Chemical difference between two HPLC columns?

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5 posts Page 1 of 1
Hi,

Please can someone explain the differences in the chemistry between these two HPLC columns:

Agilent ZORBAX RRHD Eclipse Plus C18 (50 mm x 2.1 mm, 1.8µm)

Waters Acquity UPLC BEH C18 column (50 mm × 2.1 mm, 1.7 μm)

I'm getting very little retention with the ZORBAX, even with 100% aqueous isocratic flow. I've seen some reports of others having success with the Acquity column, for the same compound as I'm developing a method for. I just want to understand the differences between these two columns before I buy one. Thank you.
Scientific Officer at Newcastle University Centre for Cancer
https://www.ncl.ac.uk/cancer/people/pro ... stley.html
Difficult to say,

both brands are excellent, They use a different base silica, and different silanes, a different way to do the endcapping.
I your case I would try a HILIC column.
Gerhard Kratz, Kratz_Gerhard@web.de
Agilent ZORBAX RRHD Eclipse Plus C18 - carbon load 9 %.
Waters Acquity UPLC BEH C18 - carbon load 18 %.
Poor retention with 100 % aqueous MP may be due to dewetting of the stationary phase. To avoid this, try to wash the column with 30-50 % ACN in water at your working flow rate, then switch to your 100 % aqueous MP without stopping the flow, and inject the analyte solutions.
Also of note, the Agilent has a 95angstrom pore size while the Waters has a 130angstrom pore size.

This can make a difference in how the water interacts with the phase and with the resolution. It isn't a huge difference but combined with the carbon loading maybe will be noticeable.
The past is there to guide us into the future, not to dwell in.
Thanks for the tips everyone
Scientific Officer at Newcastle University Centre for Cancer
https://www.ncl.ac.uk/cancer/people/pro ... stley.html
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