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high quality ammonium acetate
Posted: Tue Aug 26, 2008 8:08 pm
by ym3142
I am developing a method with 40mM NH4OAc and MeOH(50% to 95%). I saw many peaks in the blank. I am using J T Baker ammonium acetate, which is not labeled for its purity. Does any one know a quality good enough NH4OAc for LC gradient method?
Thanks,
Posted: Tue Aug 26, 2008 8:57 pm
by Kostas Petritis
We use MS grade ammonium acetate from Fluka. It is sold by Sigma-Aldrich and is part number 73594. Have it mind that the longer the equilibration time the higher the amount of impurities accumulated (i.e. start the analysis just after column equilibration).
Posted: Tue Aug 26, 2008 9:33 pm
by Bruce Hamilton
I use ammonium acetate Fractopur grade from Merck, catalogue 116103. It's for buffers, with specified UV limits. Works for me, but YMMV.
Please keep having fun,
Bruce Hamilton
Posted: Wed Aug 27, 2008 8:13 am
by aceto_81
Are you sure it comes from the ammonium acetate, and not from water, magnetic stirrer, glass ware, ....?
We ammonium acetate PA from Merck on our UPLC-PDA's with no problems, sometimes 1 or 2 peaks, but they don't disturb us as they fall far from our peaks in the gradient.
Ace
Posted: Wed Aug 27, 2008 1:25 pm
by ym3142
Thanks for all and I will look into the possible water contamination.
Posted: Fri Aug 29, 2008 6:29 pm
by ym3142
For the purpose of expressing my appreciation for people's help here, I like to report my result: In my test the Aldrich >99% NH4OAc does not gave the peak present in T J baker's NH4OAc.
Thanks and have a great Labor Day!!