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base line Hump
Posted: Sat Oct 22, 2005 5:02 am
by SRIMAN
frequently we developed one method with ion pair reagent sodium perchlorate,we are observing during HPLC run a hump coming in the base line, is there any impact of ion par reagent on base line, but on injecting the blank, the baseline is good only, no hump is observed in the base line
column : INertsil ODS
Posted: Sat Oct 22, 2005 5:48 am
by Kostas Petritis
What is your detector?
Posted: Sat Oct 22, 2005 6:15 am
by SRIMAN
Photodiode array detector
Baseline Hump
Posted: Mon Oct 24, 2005 3:07 pm
by Chris Pohl
SRIMAN,
There are quite a number of possible explanations depending upon your operating conditions. Can you tell us more about the composition of your mobile phase and your sample?
Posted: Mon Oct 24, 2005 5:20 pm
by alealbor
What is your analyte?
Can you try to use Atlantis C18 columns with 0.05 % of TFA for high polar analyte?
Alejandro
Posted: Tue Oct 25, 2005 5:31 am
by SRIMAN
the Analyte is Ramipril and the method RS, i have taken is from EP, on new column C18, the base line hump is not appearing, but after few injections the base line hump is comming before the ramipril main peak,
can any one suggest me what is the main precaution to be taken to avoid this hump in the test sample for analysis.
this base line hump is not appearing in the blank.
Baseline Hump
Posted: Tue Oct 25, 2005 3:40 pm
by Chris Pohl
SRIMAN,
I don't have access to EP methods. Can you tell us more about the composition of your mobile phase and your sample?
Posted: Tue Oct 25, 2005 6:16 pm
by Kostas Petritis
Does the base line hump is affected with different injection amounts? i.e. if you inject twice as much does the hump change as well?
Ion pairing reagents can sometimes lead to such humps, the reason that you do not see it right away is due to (maybe) that your column was not fully equilibrated. These are also refered sometimes as system peaks...
You can also try to inject another basic compound to see if you get the same "baseline hump"...