Chromatography Forum

Hi, everyone

Thank you for reading this message.

I have encountered many problems since a DX600 was installed in my lab.

Such as:
1. always to remove the air bubbles in the PDA because of calibration of pH electrode;
2. usually worry about chemical reaction of alkali eluent and CO2 because of exposure of eluent in air;
... ...

So do you have any good idea on how to run DX600 well?

Thanks for any suggestions!

zhuwj007 with regard

There are at least two ways to minimize the CO2 problem. First, carefully follow the directions in the operator's manuals. The reservoir bottles on your DX600 are equipped with an inert gas system. Pressurize the bottles with 2-5 psi of helium. One helium bottle should last a month if you have no leaks.

If you are really worried, invest in one of our electrolytic eluent generator systems. You can read all about it on our website at www.dionex.com

Since you are pumping an alkaline eluent, be sure to use the seal wash each day before you start the pump and again when you shut down the system. This will double the service interval on seals.

zhuwj007,

I'm a bit confused by your statement: "always to remove the air bubbles in the PDA because of calibration of pH electrode".

Do you mean PAD or PDA or are placing a PDA downstream from the PAD (I'm guessing this since you mention pH calibration in conjunction with DX600)? You really shouldn't need to do frequent pH calibrations with the electrochemical detector but if you are having a lot of problems, perhaps the reference electrode isn't installed properly. Does it leak? When was the last time you replaced the reference electrode? Is it discolored? If so, it needs to be replaced.

Regarding carbonate contamination, the magnitude of the problem is usually small with carbohydrate separations provided you make up your eluents from 50% NaOH and use good quality DI H2O.