By Kay B on Wednesday, February 18, 2004 - 06:10 am:
We are running a reverse phase gradient method using '50mM Ammonium acetate buffer' and '75/25 Methanol/ water' mobile phase
We are getting peaks in our blanks and also when we run a gradient with no injections. The peaks are consistent and are present each time. Does anybody have any suggestions?
By Anonymous on Wednesday, February 18, 2004 - 07:32 am:
In the vast majority of these cases, it is the water that contributes these ghost peaks.
By mgb on Wednesday, February 18, 2004 - 07:36 am:
This should be useful
http://www.nestgrp.com/pdf/Vapp/AN9805.pdf
By Anonymous on Wednesday, February 18, 2004 - 09:08 am:
replace the buffer with neat water and do the same tests. chances are that the peaks will go away. make sure the ammonium acetate is the highest purity that you can find...
By tom jupille on Wednesday, February 18, 2004 - 09:51 am:
other possible sources of contamination in the A solvent (aside from the water and ammonium acetate):
- pH electrode (if it was in contact with the mobile phase during preparation).
- residual detergent from improperly rinsed glassware
- latex glove residue from improperly handled glassware.
By Anonymous on Wednesday, February 18, 2004 - 04:23 pm:
and Tygon tubing or other plastic tubing in the water line
By Anonymous on Thursday, February 19, 2004 - 12:07 am:
You got to have some peaks from blank solvent in gradient run , if you are using lower wevelength for detection.