Dear Sameer,
In addition to Ulli’s answer, you can also use an oxidizing acid solution
such as K2Cr2O7 with dilute H2SO4 as the ZrO2 is stable against oxidation. You
should refrain from dipping the KelF and vespel plugs in!
Here is a link to a recipe for sucha a solution. There are many variations
in the literature but they just do the job of glassware cleaning.
https://webpath.med.utah.edu/HISTHTML/MANUALS/ACIDGLAS.PDF
Best regards,
Rıza
------------------------
Rıza Dervişoğlu, Ph.D.
NMR Lab. Coordinator at Wiegand Lab.,
Max Planck Institute for Chemical Energy Conversion,
working at ITMC, RWTH, Aachen,
Tel.: +49 (0) 241 80 26429
Address:
SB Chemie
Room: 38B-031
Worringerweg 2
52074 Aachen, Germany
https://mpi-cec.webex.com/meet/riza.dervisoglu
https://www.linkedin.com/in/rizadervisoglu/
ride_at_cec.mpg.de
> On 14Dec, 2023, at 22:18, Sameer Al-Abdul-Wahid <s.wahid_at_uoguelph.ca> wrote:
>
> Dear AMMRL,
>
> Over the years, many of our 4 mm MAS rotors have developed a greyish/brownish
> discolouration on the outside. It’s usually limited to the top and bottom
> sections of the rotor, and it won’t come off with water, isopropanol, or
> acetone.
>
> Does anyone know what this is and how to best clean it off? We want to clean the
> rotors so we can determine if this is an ongoing issue or due a previous probehead.
> My first thought is to try a solution of Bar Keeper’s Friend (or diluted oxalic acid),
> but could it affect the rotor in someway?
>
> Thanks,
> Sameer
>
> --
> Sameer Al-Abdul-Wahid, Ph.D. | Manager
> Nuclear Magnetic Resonance Centre | University of Guelph
> 519-824-4120 Ext. 58914 | s.wahid_at_uoguelph.ca <mailto:s.wahid_at_uoguelph.ca=
>
> http://nmr.uoguelph.ca/ <http://nmr.uoguelph.ca/>
>
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Received on Fri Dec 15 2023 - 04:57:50 MST