[3dem] corrosion on cryo-holder & inside pumping station

[Tommi White]

Hello.

We had some unfortunate issues with our Gatan 626 high tilt cryo-holder and
Gatan Turbo pumping station.  We have spent  >$5K to clean everything from
corrosion that built up both on the holder and inside the pumping station.
The corrosion looked like a whitish-blue crust on the tip of the
cryo-holder, and according to the repairman, was all over the inside of the
pumping station as well.  We eventually found the holder tip could be
cleaned/removed using Wenol metal polish on a cotton swab.

Prior to the corrosion issues, we would perform both warm-up/zeolite cycles
on the pumping station, without removing the cryo-EM grid from the holder.
Once we started seeing corrosion, we would perform the warmup cycle in the
loading station, remove the grid from the holder and perform zeolite cycle
in the turbo-station.

Negative effects included the shutter "grinding" during movement and/or the
pumping station not pulling proper vacuums to maintain cryo-temperature
during transfer with subsequent vacuum crashing.

Has anyone else experienced this?  Does anyone know what may have caused
this?  How do we prevent this from happening in the future?

Thanks in advance,

Tommi A. White, Ph.D.

Assistant Professor of Biochemistry

Associate Director, Electron Microscopy Core Facility

University of Missouri

W117 Veterinary Medicine Building

1600 East Rollins Street

Columbia, MO 65211

573-882-8304

WhiteTo at missouri.edu

http://emc.missouri.edu
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