very new to IC

[mty]

Hi All,

I'm working with a Dionex IC 5000 system, and I have some questions that I can't seem to find the answers to. I was hoping someone could help.
1. Many of the columns were purchased in 2004-2005, but were never opened. There are expiration dates of 2006 or 2007 on most of the columns. Do those expiration dates mean very much? Someone really stocked up, but didn't get down to work, so I've got quite a few, and really hate to have to re-purchase.
2. I did install one of those columns (Dionex AG21 guard column and AS21 analytical column). Using a conductivity detector, I was able to run an anion standard and separate the peaks (I didn't have the exact mix that they used in the QA report that came with the column, but did have some anions in common). I've been running standards (perchlorate and fluoroacetate in DI), and suddenly, my conductivity is all over the place--I had a fine baseline for several days, and now I'm getting humongous (21,000+ on the conductivity detector) lumps--I can't even really say peaks. Would that be due to the column being 'expired'? Or did I mess something up somewhere? Do I just need to clean everything, since the system sat for a few months without being used.
The system is sitting at 0.35 ml/min, 10mM KOH, from an eluent generator. I think this is ok for this column and this system.

3. Can anyone point me to a good resource for ion chromatography basics? I'm not sure a training course is anywhere in the budget.

thanks so much for any help anyone can give me!
mty

[M Farooq]

Hi All,

I'm working with a Dionex IC 5000 system, and I have some questions that I can't seem to find the answers to. I was hoping someone could help.
1. Many of the columns were purchased in 2004-2005, but were never opened. There are expiration dates of 2006 or 2007 on most of the columns. Do those expiration dates mean very much? Someone really stocked up, but didn't get down to work, so I've got quite a few, and really hate to have to re-purchase.
2. I did install one of those columns (Dionex AG21 guard column and AS21 analytical column). Using a conductivity detector, I was able to run an anion standard and separate the peaks (I didn't have the exact mix that they used in the QA report that came with the column, but did have some anions in common). I've been running standards (perchlorate and fluoroacetate in DI), and suddenly, my conductivity is all over the place--I had a fine baseline for several days, and now I'm getting humongous (21,000+ on the conductivity detector) lumps--I can't even really say peaks. Would that be due to the column being 'expired'? Or did I mess something up somewhere? Do I just need to clean everything, since the system sat for a few months without being used.
The system is sitting at 0.35 ml/min, 10mM KOH, from an eluent generator. I think this is ok for this column and this system.

3. Can anyone point me to a good resource for ion chromatography basics? I'm not sure a training course is anywhere in the budget.

thanks so much for any help anyone can give me!
mty

Hamish Small, the founder of IC, wrote a nice thin book on ion chromatography which pretty much covers all the fundamentals but it is slightly old but still a good one for an introduction. A review chapter is also available here: http://www.sciencedirect.com/science/ar ... 7004800101.

If the background conductivity is abnormally high, check the suppressor. The suppressor may have turned off for some reasons and ensure that it is being regenerated. It has nothing to do with column expiry.

The latex coating on IC columns is ultra-stable on those polymers, however in relatively alkaline storage conditions for 10 years, you might see a decrease in nominal capacity due to the chemical properties of quaternary ammonium groups in alkaline medium. Check this influence by injecting divalent ions such as sulfate with the recommended eluent such as carbonate or hydroxide. If the retention time of divalent ions is within the expected range (say < 10% decrease), the column should still be good.