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Flushing Cu mobile phase
Posted: Thu Dec 06, 2012 3:06 pm
by mark.owens
Dear users,
I have a method using copper in the mobile phase and was looking for guidance on flushing the system to make sure all of the copper has been removed from the system. Could I please get input on the best method/mobile phase to flush the system with?
Regards,
Mark
Re: Flushing Cu mobile phase
Posted: Thu Dec 06, 2012 3:23 pm
by DR
I'd be inclined to pull the column and flush w/ some 2-3N HNO3, followed by lots of water.
Re: Flushing Cu mobile phase
Posted: Sat Dec 08, 2012 7:40 pm
by Karen01
I assume you are using a chiral column... and I'm probably running a similar one...
What we do is take the column off, flush the system well with water and then with organic in preparation for a different column/mobile phase...
We don't see an issue... What is the problem you see?
- Karen
Re: Flushing Cu mobile phase
Posted: Mon Dec 10, 2012 1:50 pm
by mark.owens
I assume you are using a chiral column... and I'm probably running a similar one...
What we do is take the column off, flush the system well with water and then with organic in preparation for a different column/mobile phase...
We don't see an issue... What is the problem you see?
- Karen
Karen,
I haven't seen an issue yet. Last time I tried the nitric acid flush suggested by another reader here, but it took several hours to flush all of the nitric from the system so I was looking for an alternate flush procedure to make sure the copper was gone. I am actually determineing EDTA and DTPA on a RP column and have nightmares about the copper carrying over into another column and analysis.
Thanks for your reply,
Regards,
Mark
Re: Flushing Cu mobile phase
Posted: Wed Dec 19, 2012 11:02 am
by prepcolumn
For EDTA: try HAMILTON PRP-X100, 4.1 x 150mm 10μm, 250 nm, pH:3.5 buffer:acetonitrile (75 : 25) after complexation of EDTA with ferric chloride..
Good luck
Re: Flushing Cu mobile phase
Posted: Wed Dec 19, 2012 3:55 pm
by Consumer Products Guy
I am actually determineing EDTA and DTPA on a RP column and have nightmares about the copper carrying over into another column and analysis.
Mark, we do EDTA and DTPA on a C8 column using copper in the mobile phase, and don't see any real issues. I feel for this that it's best to dedicate a column for this assay, but that may be more because the mobile phase we use is aqueous.
We flush the system and column with HPLC H2O for 15 minutes at 2 ml/min., then pump through with about 20% HPLC methanol or 20% acetonitrile.
Re: Flushing Cu mobile phase
Posted: Fri Jan 04, 2013 7:48 pm
by mark.owens
I am actually determineing EDTA and DTPA on a RP column and have nightmares about the copper carrying over into another column and analysis.
Mark, we do EDTA and DTPA on a C8 column using copper in the mobile phase, and don't see any real issues. I feel for this that it's best to dedicate a column for this assay, but that may be more because the mobile phase we use is aqueous.
We flush the system and column with HPLC H2O for 15 minutes at 2 ml/min., then pump through with about 20% HPLC methanol or 20% acetonitrile.
Would it be possible for you to share your method for the EDTA/DTPA? Will send you my e-mail address if it is OK for you to share.
Re: Flushing Cu mobile phase
Posted: Mon Jan 07, 2013 4:04 pm
by Consumer Products Guy
Would it be possible for you to share your method for the EDTA/DTPA?
Unfortunately, that is considered proprietary, from a supplier of chelating chemicals. All I can share is that the mobile phase is a mixture of quaternary ammonium surfactant and copper sulfate at pH 4.2 with acetic acid/NaOH (no organic solvent) and samples are made up in dilute copper sulfate. RP-8 and UV detection is used.