HPLC Peak separation

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janet79's picture
HPLC Peak separation

Dear Analysts,

I am having a poblem in HPLC Peak separation. I'm currently testing on a AI :Glufosinate Monoammonium.
The method seems to be useful to quantify single AI as well as a formulation that contains 2 AI. However, we have a new formulation that contains 3AI. Therefore , using this method, one of the AI is eluted at the same retention time as Glufosintae RT. How can i solve this. Below are the following parameters:

Column type    
Thermo Hypersil SAX (10µ)

Mobile phase      
0.1 mol/l of dihydrogen phosphate solution

Flow rate     

Column oven  

Injection volume  



Dr. Analytical
Dr. Analytical's picture
Dear Janet:

Dear Janet:
Your analytes are eluting too soon after the void volume. You did not give us the column dimensions, so I can not exactly calculate the void volume, but from your chromatograms, the peaks are coming out too soon.

Flow rate will not change the separation very much, so do not use that parameter.

In an ion exchange system, you increase retention by decreasing the concentration of your buffer.  Try smaller concentrations of the phosphate: 0.08, 0.05, 0.02, 0.01, etc.