1. How do the Capillaries provide different amounts of flow?



2. At which pH will my method optimize with these capillaries?



3. Will my analyte absorb the polymer?



4. Which column widths do these capillaries come in?



5. Can I use the MicroSolvCE Window MakerTM or similar units on the Zero EOF or Controlled Flow Capillaries?



6. What is the High Flow Rate based on?



7. What good is a Zero EOF Column?



8. Is the conditioning of the Controlled Flow Capillaries the same as with a bare fused silica capillary?

1. How do the capillaries provide different amounts of flow? [top]
We coat the bare fused silica with a proprietary polymer that has a large amount of Sulfonic acid groups exposed to the lumen of the capillary. The different flow rates of the columns are due to differing amounts of polymer. The more the polymer the less of a flow.

2. At which pH will my method optimize with these capillaries? [top]
These capillaries columns are pH independent. What that means is the flow does not change significantly with different pH levels. The optimal pH will be the pH at which your analytes separate best.

3. Will my analyte absorb the polymer? [top]
The Controlled and Zero EOF Capillaries usually produces a very low sample to polymer interaction and absorption. Your analytes could be different.

4. Which widths do these capillaries come in? [top]
These capillaries are available in both 50m and 75m ID width. The length of the capillary is 1 meter.

5. Can I use the MicroSolvCE Window Maker^TM or similar units on the Zero EOF or Controlled Flow Capillaries? [top]
It is not normally recommended that one use high heat to remove the polyimide coating on the capillary. This could create a “void” in the wall coating and produce erroneous results. It is best to use chemicals to remove the polyimide in this case. Be sure to follow good laboratory practices when using hazardous chemicals.

If you use the MicroSolvCE™ WindowMaker™, please contact Technical Service for an approved technique for removing the polyimide from the Zero EOF or other Controlled Flow capillaries. Call at 1.732.578.1777 or email us.

6. What is the High Flow Rate based on? [top]
The terms High, Medium and Low are based on a relative flow when compared to Bare Fused Silica Capillaries. The Controlled Flow capillary always is slower than bare silica but the High Rate is the highest of the Controlled Flow capillaries. A set of conditions on a bare silica column that provides a migration time of 3.2 minutes for a neutral marker will provide a migration time of 4.3 minutes for High, 6.5 minutes for Medium and 8.2 minutes for Low when using Controlled Flow capillaries with that same marker.

7. What good is a Zero EOF Capillary? [top]
There are many uses for Zero EOF in HPCE. One use is to allow analytes to separate based on electrophoretic mobility only. The Zero EOF capillary is an excellent choice for this technique because, regardless of the pH you use to ionize your analytes, the flow will still be zero. Another use is IEF.

8. Is the conditioning of the capillary the same as with a bare fused silica capillary? [top]
No. Inside the front cover of the column case is a special set of conditioning steps that must be taken. It is important that these conditions be followed. You can also see these conditions on our website by clicking on this link: Controlled Flow capillary Conditioning Steps.