cleaning phenyl column

[rm]

Hi all,

I want to know if somebody have information about cleaning (rejenerating) phenyl columns. I am using Ace 5 Phenyl column. My problem is peak tailing. After using SDS for ion pairing, this problem have occured. I have washed the column with water, then with methanol while injecting DMSO. After this procedure, all the peaks have splitted. What can I do now?

Thanks a lot in advance,

[Rick Jagielski]

In previous posts on this board they discussed DSMO and its effects on some columns. In particular there was some discussion about how it creates a high pressure zone as it moves through the column and will sometimes create a void in the packing at the head of the column. A partially blocked frit or a void in the packing can often cause peak splitting.

Thanks
Rick

[tom jupille]

How old is the column (time or number of injections)? Peak splitting can be caused by a void space at the head of the column, especially an old column.

[rm]

The column is not old (approximately 50 standard injections). How can solve the column void problem?

Thanks a lot,

[tom jupille]

If the column has had only 50 injections, I'd contact the supplier and talk to them about either a replacement or suggestions specific to that column.

After you have talked to them, do the following:

1. If possible, back-flush the columns (your usual mobile phase and flow rate, but with the column direction reversed). Be sure to ask the supplier if this is OK (not all columns can be back-flushed!). After 15 minutes or so, return the column to its original direction and re-test.

2. If the back-flush didn't solve the problem (or if the column cannot be back-flushed), change the inlet frit (you will have to obtain a replacement frit or fitting from the supplier (this will definitely invalidate any warranty, which is why you want to talk to the supplier first!).

3. While you have the end fitting off, check to see if there is a void at the head of the column. If there is a headspace, it can (sometimes) be fixed by "topping off" the space with either small glass beads, or packing taken from the outlet end of an old column. This is a fairly time-consuming process, and worth while only if the value of your time is very low (my feeling is that it's usually more cost-effective to replace the column).

Good luck! (you'll need it).