Chromatography Forum

Hi All,

Naive question:

Would it be ok to use a column guard: 2.7 μm particle size, L × I.D. 5 mm × 2.1 mm with a column: 2.7 μm particle size, L × I.D. 5 cm × 3 mm

Thanks a lot,

K.

Hi All,

Naive question:

Would it be ok to use a column guard: 2.7 μm particle size, L × I.D. 5 mm × 2.1 mm with a column: 2.7 μm particle size, L × I.D. 5 cm × 3 mm

Thanks a lot,

K.

It will usually work ok to have small differences in the guard and analytical column on HPLC since most times they have a very short length of tubing between them. Even if they are the exact same sizes, there is still that small connecting tube of a different I.D. between them.

Hi All,

Naive question:

Would it be ok to use a column guard: 2.7 μm particle size, L × I.D. 5 mm × 2.1 mm with a column: 2.7 μm particle size, L × I.D. 5 cm × 3 mm

Thanks a lot,

K.

Don't bother about the different diameter. But 5 mm is rather long for a pre-column: The volume of your guard column is about 5 % of you analytical column, so you might expect small shift in retention time.
Try out and see (and tell us) what happens.
Jörg

Hi All,
So, I just got an Ascentis Express C18 from Sigma Aldrich. They literally say to run it at 1mL/min (which is very high for a 3mm diameter). They also say that you can run it without a guard because they are confident that you won't clog... Yet I decided to use a guard, just in case : and it works just fine!