Peak Tailing [August 24, 2004]
Posted: Sun Aug 29, 2004 8:36 pm
Peak Tailing
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By Shaun Barford on Tuesday, August 24, 2004 - 04:52 am:
I am separating creatinine (biogenic amine) from a complex mixture using SCX ion-exchange. My mobile phase is 0.02 mol l-1 of acetic acid and 0.2 mol l-1 of sodium acetate. Initially the creatinine peak is very sharp but as time goes on the peak tails more and more. Does anyone have any explanation for this? Any ideas and suggestions welcome, thank you
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By Chris Pohl on Friday, August 27, 2004 - 09:25 am:
While I was unable to find any tabulated data to support this hypothesis (i.e. I couldn't find any metal complexation stability constant data on creatinine), one possibility is: metal contamination of your stationary phase may be causing tailing due to a complexation interaction between creatinine and the metal contaminants. You should be able to test this hypothesis by making several injections of relatively concentrated disodium EDTA solution (a 0.1% solution should be sufficient). If peak shape is significantly improved, metal contamination is likely the culprit. In this case, you may need to place a chelating trap columns prior to the injection valve to prevent the problem.
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By Shaun Barford on Tuesday, August 24, 2004 - 04:52 am:
I am separating creatinine (biogenic amine) from a complex mixture using SCX ion-exchange. My mobile phase is 0.02 mol l-1 of acetic acid and 0.2 mol l-1 of sodium acetate. Initially the creatinine peak is very sharp but as time goes on the peak tails more and more. Does anyone have any explanation for this? Any ideas and suggestions welcome, thank you
-------------------------------------------------------------------------------------------------------
By Chris Pohl on Friday, August 27, 2004 - 09:25 am:
While I was unable to find any tabulated data to support this hypothesis (i.e. I couldn't find any metal complexation stability constant data on creatinine), one possibility is: metal contamination of your stationary phase may be causing tailing due to a complexation interaction between creatinine and the metal contaminants. You should be able to test this hypothesis by making several injections of relatively concentrated disodium EDTA solution (a 0.1% solution should be sufficient). If peak shape is significantly improved, metal contamination is likely the culprit. In this case, you may need to place a chelating trap columns prior to the injection valve to prevent the problem.