Hi Ken,
Paramagnetic relaxation is usually (mostly? I might be going out on a limb
with this one) linear, so regardless of the relaxation agent you go with, you're
always going to have this issue. So a stock solution in H2O and/or D2O is the
way to go here. I had not appreciated the issues with the use of GdCl3 that
Clemens noted, but for what its worth, the only Bruker doped water sample I
have has a T1 of 0.21 s at 298.0 K. Would be interested to see how much
variability there is in the field...
If you mean "I can't get the T1's I want for some peaks without unacceptable
line-broadening of others", then that's a different proposition so you might
want to consider some of the Gd chelates as used in metabolomics here
https://onlinelibrary.wiley.com/doi/10.1002/anie.201908006 and here
https://www.sciencedirect.com/science/article/pii/S1090780723000976?via*3Dihub,
or CO2 reduction analysis here
https://pubs.acs.org/doi/10.1021/acs.jpcc.2c03448.
They report a handful of T1 measurements under different conditions that might
point you in the right direction.
Although in all cases you're left with extra work if you want to recover the
sample afterwards, which may or may not be problem depending on the application.
Thanks
Geoff
From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Kenneth Sharp-Knott
Sent: Tuesday, August 8, 2023 4:52 PM
To: ammrl_at_groups.io
Subject: [External] [AMMRL] Water soluble relaxation agents? Experiences with GdCl3?
Hi Everyone,
I was hoping to get some insight or tips into water soluble NMR relaxation
agents. I know that GdCl3 and Copper Sulfate are commonly recommended, but
I would like some specifics on suggested concentrations and hear about your
experiences using these.
In my own experience they don't seem to have a general one size fits all
concentration. There is a fine line between too much and too little GdCl3.
I'm trying to put together a recommended protocol for students needing a
water soluble relaxation agent.
Best Regards
--
Ken Sharp-Knott
Manager of Analytical Services and the NMR Facility
Department of Chemistry
Virginia Tech
(540)267-6502 (Cell)
(540)231-0885 (Office)
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