Hi,

We are going to a ion chromatography system. Does anyone have any idea which one is good? Thanks.

Go with a Dionex, they specialize in ion chromatography.

Is that possible to connect Dionex conductivity detector with other vendor's HPLC system? Will the mellinium software be able to control that detector? What is the cost effective way? Thanks.

There is no reason that you can not connect your Dionex detecor to some exisiting HPLC hardware. Millennium software will not control a Dionex detector. It will however, be able to accept data from that detector through a SATIN box. This assumes that the Dionex detector has some level of stand alone control. My advice is to buy a dedicated IC system. Do not peice together a system from multiple vendors using equipment that was never meant to work togeteher. Get in touch with your local sales reps from all the major companies and tell them what you want to do. Explain your exact applications and ask them all to show you examples or better yet, give them your samples and expectations and get those vendors to run it a few times. Pick the system that best suits your needs. People often ask for opinions about hardware and software in this forum which is mostly useless. Only you know what you really need. Talk to all the vendors, be honest and upfront with them about your applications and expectations and you will get the system you need.

Th Dionex system is set up so that the sample only comes in contact with PEEK. This yeilds better sensitivity through a reduction in baseline noise. One drawback is the inability to use this system for HPLC work with THF mobile phase.

Can someone explain the difference between a conductivity detector and an electrochemical detector? Would I be able to detect the presence of inorganic ions with an electrochemical detector?

I know that the ECD works by the oxidation-reduction of organic compounds, but would it also measure a change in concentration of inorganic ions?

We are using a Dionex column/suppressor combination for ion chromatography. We are trying to validate the method to determine the amount of chloride and phosphate anions present in a sample. We noticed during the accuracy section that when we spiked in additional chloride and phosphate to the starting material all of the amounts came out higher than excepted. Typically our samples are run in the presence of protein. We have tried running the samples with and without protein present, and no difference is seen in the accuracy. Any ideas why our results might be coming out high?

The problem may be with your sample (or spike) pH. What pH is your sample? Is your spike the same pH? Another problem that sometimes causes this is a coating of biological material on the sample lines leading to the loop and the loop itself. Such a coating can retain ions from samples and bias results. Spiked additives can elute ions bound to this coating resulting in high recoveries for your spike, especially if the spike is at extreme pH. You might want to try replacing these and see if this helps.