Guard columns with UPLC

[adam]

I recently came across something that said "guard columns will significantly decrease your efficiency" (this was in reference to "standard" HPLC).

Personally, I think this is a bit of an exageration, but it got me thinking: what about UPLC? We all know that UPLC systems are much more sensitive to dead volume than standard systems. Are people who do UPLC generally working without guard columns? Or reporting more difficulty with them?

This seems like a critical issue. Personally, in my 16 years doing HPLC, I almost never run without a guard column.

Very interested to hear some thoughts on this.

[Kostas Petritis]

I do not agree with the statement that guard columns will significantly decrease your efficiency... unless you use some "ancient" way to connect the guard column to the main separation column... With modern guard column the lost of efficiency is minimal.

Even in UPLC guard columns are used, although they are specifically designed to introduce minimal volumes to the system and of course resistant to the UPLC pressures... Waters calls their guard columns Vanguard and if you see chromatograms with and without guard column, the only way you can differenciate one from another visually is from their retention difference...

[Uwe Neue]

Properly designed guard columns will not affect the efficiency of your analytical columns or may even increase their efficiency slightly. The exact same is true for UPLC. The design of a good UPLC-quality guard column was not a trivial enterprise, but the bottom line is (as already stated above by Kostas) that the impact of the Vanguard guard column on the efficiency of the UPLC separation is negligible.