General ion chromatography questions...

[SteelRookie]

Hey Folks,

I've spent the last 2 months working on our brand new ICS-5000 (Dionex) and I find myself asking a lot of questions that are likely just normal beginner's questions. I'm wondering if anyone can point out a good book or website that covers things like:

How often do you replace a guard column?
How can you tell when your analytical column needs replacement?
My peak areas are very slowly increasing over time. Is this normal?
What happens if you ignore the warnings and turn on eluent flow without the suppressor on?

We're just running EPA 300.0 for anions, so its a pretty standard setup with carb/bicarb eluent, AS22 column, conductivity detection, auto-regenerating supressor. I know the theory, and I can use the thing well enough. (Chromeleon 7 is very nice, by the way) All I need is a book like "IC for Dummies" or some such that I can reference for answers... any suggestions?

[Uwe Neue]

My book on "HPLC Columns" has a good section on troubelshooting.

You replace a guard column when you see the first signs of deterioration of the separation. Once you have experience - say that it always occurs after about 300 injections - you replace it just before.

The analytical column needs to be replaced if you have significant deterioration in peak width (plate count) or retention, or when you see double peaks.

Something is wrong when peak areas are increasing with time, but this is usually not a column problem. Injection? Sample evaporation? Detection?

[danko]

SteelRookie,

The peak areas will stop increasing after some time. What you see is column saturation. If you want to shorten the time you could load some larger amounts of the sample - f. ex. the double of what you'd normally load when taking a new column into use.

Best Regards

[HW Mueller]

When working with radioaktive substances, with radiodetection, I noticed that most if not all analytes have tails or even extremely flat peaks following the main peak. One does not see this in UV, as an example, as the amount is insignificant. I don´t know what the very long range effect is, but I suspect it is an insignificant amount that stays in the column.
Generally I would be very worried that I developed the correct method if this phenomena was operating to an interfering extend. Öne should remeber that any system that requires an equilibrium coating of a column is not thermodynamically/kinetically robust.

[danko]

Hans, I’m with you on the â€

[SteelRookie]

Thanks everyone for the input. That answers the questions that were worrying me the most. I'd still like to find some kind of good IC reference book if I can find one.

[jschibler]

Good coverage of modern IC is provided in the books by Joachim Weiss and by Paul Haddad. See http://www.dionex.com/en-us/documents/lp-84871.html.