Chromatography Forum

Hi,
I am going to use a chelating agent in my mobile phase but because I am using a ELSD it has to volatile. Do anyone have a suggestion?

Dear Anders,

I am not sure about what you are trying to do, but ACAC (Acetyl Acetone) is volatile and is a good chelatin agent. I hope this information helps.

Good Luck,

josebenjamin

Dear Josebenjamin,

My analyte is a strong chelating compound and I think it is therefore I have problems analysing low concentrations. Therefore I want to use a chelating agent in my mobile phase to prevent my analyte chelate with metal ions and thereby lower the LOD. Does it sounds right?

Best regards

Anders

Dear Friend,

It is indeed normal practice to add chelating agents such as EDTA to the mobile phase to avoid complexation by analytes. You could try ACAC, but it is likely your background signal will increase, how much?, it all depends of how effectively ACAC chealtes with metals in your system.

It is also possible that your system could be "passivated" if you make some ACAC inyections (perhaps in solution) in your system (not adding it to the mobile phase). This way some of the metal activity in the systems would be blocked, and then it could give better results with your analyte.

Another solution, and a more complicated one, would be to use a "metal free system". This means a high purity silica column in a plastic cartridge and with polymeric frits, and plastic lines.

Good Luck

josebenjamin

Anders,
Maybe another approach is to complex the analyte on purpose with something like copper or zinc and then analyze for the complex.

Regards,
Mark