Chromatography Forum

Hi all I am new to CE. I have just acquired an Agilent 1600 CE system and have some questions.

-Is it possible to prepare capillaries yourself for this instrument? I understand that the window needs to be 8-9cm from the end and 1.5 to 2mm wide (very small window). I saw instructions using a splicer of some sort is there a way to shield the area on either side and burn it yourself?

-Vials. Can I use standard/cheap screw cap autosampler vials? Hydrodynamic pressure injection isn't very much (50mbar) so it doesn't seem like it would need specialty robust vials and caps

-Degassing is seems a bit cumbersome to sonicate such small vials full of liquid in the sonicator bath. Do they make a special floating holder I can buy or something.

-Is high pressure (gas hookup) needed for simple CZE or MEKC in open capillaries.

-How important is using the replenishment system when you are not running tons and tons of samples?

-How do you prevent microbial growth in buffers?

-Are there any trainings available? I'm am learning the best I can from books, manuals, and the like but there is a paucity of information available compared to HPLC and other more widespread techniques especially for specific instruments like installing the capillary.

Thank you very much for any advice you can give me. CE is new to me but since my lab doesn't have the resources for an HPLC CE seems a good alternative.

- You can prepare the capillaries yourself, i usually use some tin foil to protect the capillary when burning the window, i think the best way is to use an electric burner with a nichrome wire
- I don't think screw caps are compatible, only snap caps
- There are commercially available floating holders, but you can easily make some of styrofoam
- High pressure is not needed for simple CZE, only if you do CEC or CGE
- Replenishment is needed when running a lot of samples, i usually use the buffer in vials for 1 to 3 analyzes

Thanks for your reply. I've messed arround with a piece of capillary burning windows with a utility lighter which worked well but made the windows to large though I don't understand what effect having too large a window will have (I read it has deleterious effects on sensitivity) other than to have a larger weak point in the capillary. The only purpose for the polyimide is to add strength. If I shielded it on both sides with foil and burn would that work?

I read the recommendation for the snap caps but am not sure why they are needed over screw caps. The manual says definitely no metal caps.

Yes, use pieces o tin foil to shield both sides. The length of the window will only affect the capillary strength, a larger window will make it more susceptible to breaking when removing itfrom the alignment interface.

Ok Thanks.

I can see why the manual calls for the snap caps. I see the instrument lifts the vial to the electrode/capillary where the cap presses against the top which helps maintain the seal and pressing down on a screw cap does nothing. I'll order some Polyurethane snap caps. My usual supplier only carries polyethylene caps but the manual says only use those for samples and not for multiple punctures.

Instead of aluminum foil I found taking two small lengths of 1/16" steel tubing (scrap from GC plumbing), inserting the capillary and having ~2mm in between them exposed and using a utility lighter works pretty well. I then wipe off the char with a kim wipe.