We would recommend against using different particle sizes and stationary phasess for guard and analytical column combination. That being said, the Cogent 2.o™ columns are valuable so it may be worth trying and seeing if the guard column does or does not have an adverse effect on efficiency in the method. If the purpose of using a […]
Category: Guard Columns FAQ
Can I use a silica or Silica-C guard column with an analytical column of a different phase?
An ordinary silica or TYPE-C™ silica guard column could be used to trap impurities from your samples if that is what you are trying to do. Sometimes different phase columns are used to do 2DLC separations as well. However, we do not recommend using different phases together (for guard and analytical) because of the changes […]
Does the direction in which a guard column for HPLC is placed in the holder matter?
No, the guard column cartridge can be placed in the holder in either direction. The label on the column does not indicate a particular direction to place the column in the holder. The guard columns have no flow direction in the holder. Click HERE for Ordering Information Including Guard Column Holders
How do I connect a guard column with my analytical column?
A convenient way to easily connect the analytical column to the guard column holder is to use our column couplers (See link below). Alternately you can use PEEK tubing and ferrules instead. This setup is less ideal though because cutting tubing can be difficult to get perfect cuts and poor tubing connection can cause band broadening. The column […]
Is your guard column holder supposed to close all the way?
When you insert the guard column cartridge and close the holder, you may notice that the holder does not appear to close all the way. This is normal and within the design specifications of the unit. With the cartridge placed in the holder, simply give the holder a quarter turn with a wrench and this […]
Protecting HPLC Analytical Columns: When to use Guard Columns vs. Inline Filters.
All Filters including an Inline Filter are designed solely for preventing un-dissolved Particulate Matter from reaching the Analytical Column or the HPLC Instrument. Note that the analytical Column does have Porous Frits on the inlet (and outlet) that will also prevent some un-dissolved Material from reaching the Column bed, but if they become clogged, they […]
What is the maximum pressure of your guard columns?
The maximum pressure is the same as the analytical columns. The standard 4um columns are rated up to 6000 psi but no more than 4500 psi is recommended during the run. The 2.o™ phases are suggested at no more than 9000 psi. A PEEK column coupler will suffice unless you are using UHPLC, which is […]
What type of tubing do I use to connect the guard column holder to analytical columns?
The best choice is to use a column coupler to minimize dead volume. As for the appropriate ID, you should use the same ID as in your HPLC system tubing. Click HERE for Ordering Information that includes Column Couplers
Which HPLC column sizes (ID) are the Guard Column Holders (cat# 82000-GH) compatible with?
The Guard Column Holder can be used with any guard column in the range of 1.0mm – 4.6mm ID. In addition to the holder and guard column, you will need a coupler which is used to connect the guard column holder to the analytical column. We do not suggest using these guard columns with analytical columns outside […]
Will a different guard column hardware system different from the Cogent system affect my results when using a Cogent HPLC column? – FAQ
If the guard column is packed well with the same stationary phase as the analytical column and the guard system hardware has no or very little inherent dead volume, it should not affect the results you get compared to the Cogent guard system. It is important to note that any guard column or extra tubing […]