Chromatography Forum

Hi all,

I am having issues in detection of nitrite in environmental samples because of carbonate presence (in the samples). I use Dionex ICS 2000 system with AS18 column, KOH eluent: 30 mM, 1 ml/min.

Unfortunately, changing the eluent concentration from 30mM to lower level (recommended 23mM) could not fix the problem. Gradient elution messed up the detection of the other analytes of our interest. Any other ideas?

I am thinking of ordering a CRD, but do not know anybody who have any experience. I do not know the lifetime of the device, does it require any regeneration during its use. Any help?

Thanks,
Jozsef

I use an AS22 for anions and don't see the carbonate issue. I used to run the AS18 and switched for just that reason. I haven't tried the CRD though.

Hey JoRa,
I have a similar setup: ICS-2100 with AS18, KOH eluent. I use a CRD plumbed between the suppressor and the detection cell to eliminate carbonate because it was interfering. I don't know the lifetime, but I've been using it for 6 months and it's doing just fine. Because it is between the suppressor and the cell, the regen from the suppressor flows through it and does not require a different regen setup. It seems to be low-maintenance and works great for me.
Good luck!
Lauri

Thank you for all!

I have started to use a CRD and it works great. Almost all of the carbonate ions could be eliminated.

JoRa

Sorry What is a CRD? I'm analyzing ions in water .As per your description it can help me too.

CRD stands for Carbonate Removal Device. It is an accessory you can buy from Dionex if you are using a Dionex IC. Try this link: http://www.dionex.com/en-us/products/accessories/reagents-accessories/crd/lp-73608.html If not, other manufacturers might have something similar.

Thank you