LC Preventative Maintenance Tips and Tricks – The UltraShield

We’re providing a creative trick for extending guard cartridges and column lifetimes.  This preventative maintenance consumable also acts as a handy troubleshooting tool for problematic back pressure readings.  Drum roll….The UltraShield!

Normally, the UltraShield is used as an affordable UHPLC pre-column filter and takes the place of a guard column.  These filters have minimal effect on efficiency with all UHPLC columns and systems and, when properly used, should not impact separations.  However, Paul Connolly at Restek had an idea to use the UltraShield as a preventative maintenance consumable for extending column and guard cartridge lifetimes and as a simple check point for troubleshooting back pressure issues which are common pain points for cannabis testing.  The UltraShield can be utilized for many new and refurbished LC systems that are frequently used for potency testing.  You can add the UltraShield in several locations in front of your guard cartridge and analytical column.  But ideally, adding it right after the injector will protect as much of your system and consumables as possible.   For this modification you’ll only need two 1/4” x 5/16” wrenches ( and an UltraShield as pictured below.

After acquiring these parts it’s time to get to work!  In the picture below, you can see a common 6 port valve set up.

To install the UltraShield, simply loosen and remove the sample loop fitting.  Then properly seat and tighten the UltraShield between the six port valve and the sample loop fitting.  In the picture below, you can see the completed installation of the UltraShield.

It’s that quick and simple!

Now your six port valve, lines, guard cartridge, and analytical column have an extra layer of protection from those dirty and complex cannabis samples!  In addition, when you notice elevated back pressure issues, you can easily change this filter out with another to see if the problem is corrected.  When you add the costs for replacing a guard cartridge and analytical column compared to replacing an UltraShield, it’s an affordable preventative maintenance consumable labs should be utilizing.

Helpful Tip:

I learned the hard way to keep UltraShields in a plastic container.  The ferrule for the UltraShield rolled off the lab bench during installation.  It took me a LONG time to find the PEEK ferrule.  It’s in the picture below….have fun spotting it (I had a joyful time with the task).

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