regarding two compounds having same Rt

[rrm1987]

I am currently working on Metal complexes and its seperation in HPLC.Individually i analysed the metal complex.Three metal complexes has same Rt.How to seperate this?
conditions are:FR=1mL/min(isocratic);Mp=CH3OH:THF:Buffer pH-6=30:30:40;C18 Luna from Phenomenex.
Suggestions required to slve this issue.

[Gerhard Kratz]

2 things I would try first:
play around with pH of your buffer - acidic and basic
try a HILIC column
Good luck

[prepcolumn]

what are your complexes?

[Vlad Orlovsky]

A lot of metal complexes do not survive chromatography. It is possible that whatever you see is a portion the complex (organic molecule) and if it the same for all three you might see only one peak,

[rrm1987]

A lot of metal complexes do not survive chromatography. It is possible that whatever you see is a portion the complex (organic molecule) and if it the same for all three you might see only one peak,

What would you suggest me to go ahead in seperation of those complexes?

[Kristof]

Regarding complex stability in chromatography - if those compounds form complexes with the same metal, would adding metal salt to mobile phase help?

[edited for clarity]

[rrm1987]

Regarding complex stability in chromatography - if those compounds form complexes with the same metal, would adding metal salt to mobile phase help?

[edited for clarity]

the same ligand complexed with different metals not same metal complexed with different ligands.

[rrm1987]

what are your complexes?

Cobalt and copper complexed with quinolyl azo dimethyl amino phenol

[prepcolumn]

what are your complexes?

Cobalt and copper complexed with quinolyl azo dimethyl amino phenol

Check the paper at this link.

http://www.ncbi.nlm.nih.gov/pubmed/12509050

If you think that it works and cannot reach full paper let me know

[Vlad Orlovsky]

What is the task? If you task is to quantify each complex you can look at cobalt and copper in ELSD, and your ligand in UV and do calculation on each complex assuming that you know structure of the complex and you don't have excess of free metal ions and free ligand floating around.

[rrm1987]

what are your complexes?

Cobalt and copper complexed with quinolyl azo dimethyl amino phenol

Check the paper at this link.

http://www.ncbi.nlm.nih.gov/pubmed/12509050

If you think that it works and cannot reach full paper let me know

i tried that method.That method was reproducable.

[rrm1987]

What is the task? If you task is to quantify each complex you can look at cobalt and copper in ELSD, and your ligand in UV and do calculation on each complex assuming that you know structure of the complex and you don't have excess of free metal ions and free ligand floating around.

i am planning to quantify Cu,Co,Zn,Mn and Fe simultaneously in single run.will this method help?