[3dem] Ambient humidity and glow discharger efficiency?

Wed Oct 8 09:55:34 PDT 2025

 Hello,

Not really wanting to hijack the thread but we have had some similar issues and honestly did not think about the glow discharger.  The one thing we have been thinking about is the room it and our plunge freezers are in.  The humidity is pretty high generally since Oklahoma is humid, 55-65%.  Do most facilities have a “dry” room to place these in and would smaller room with a decent dehumidifier be sufficient.

Thank You for any insights on where to ideally place the equipment or at least a better spot then they aer currently in.

Best,
Len Thomas

Leonard M. Thomas, Ph.D.

Biomolecular Structure Core Director | Chemistry and Biochemistry
Oklahoma COBRE in Structure Biology
The University of Oklahoma
101 Stephenson Parkway | Norman, OK 73019
405-325-1126 | https://urldefense.com/v3/__https://www.ou.edu/structuralbiology/cobre-core-facilities/mcl__;!!Mih3wA!BFH-eAui2b6VrXb9SawErsenNfhq6yJP-BojZtnLx4pDAQpOZHKBEZU_MO8u1T43qpMG0PMyTYrU95g-f4s$ 
From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of Daniel Asarnow via 3dem <3dem at ncmir.ucsd.edu>
Date: Wednesday, October 8, 2025 at 11:34 AM
To: Talya Levitz <tlevitz at crystal.harvard.edu>
Cc: 3dem at ncmir.ucsd.edu <3dem at ncmir.ucsd.edu>
Subject: Re: [3dem] Ambient humidity and glow discharger efficiency?

External Email

Forgot to ask - this isn't from a single box of grids is it? Some batches especially need chloroform washing. We have also had users not close the Glocube all the way, then it doesn't actually glow (there's an interlock relay you can hear fire when the door seals). Similar issue can occur on the Pelco if the O-ring is worn out. I also highly recommend the rubber protector O-ring for the glass cylinder, it helps it seal in addition to protecting the jar.

Best,
-da

On Wed, Oct 8, 2025 at 6:43 AM Talya Levitz <tlevitz at crystal.harvard.edu<mailto:tlevitz at crystal.harvard.edu>> wrote:
Thanks, Daniel.

In our case we can see that the hydrophilicity is an issue immediately, although it will decrease over time. We start to see issues in grid quality after 10-30 minutes of sitting out in the air post-discharge, which is faster than I have seen in other labs. I wonder if whatever is causing the decrease in overall hydrophilicity is also contributing to the length of time the glow discharge can last.

It definitely can't hurt to clean our block and discharger. We don't do anything with it except glow discharge unmodified grids, but people touch it with their bare fingers, so I'm sure there is grease on everything from that.

Good to know regarding the destroying the film. Another easiglo we occasionally use destroyed the film at much lower time than 5 minutes at 20 mA, but it tends to randomly destroy carbon films anyways, likely because it is very dirty.

I have gotten a good number of offline responses — will send a summary out for folks in a couple days!

Talya Levitz, PhD

Scientist I
talya_levitz at dfci.harvard.edu<mailto:talya_levitz at dfci.harvard.edu>
Pronouns: they/she<https://urldefense.com/v3/__https://www.stonewall.org.uk/resources/workplace-trans-inclusion-hub/a-beginners-guide-to-pronouns-and-using-pronouns-in-the-workplace__;!!Mih3wA!Ap0nBboRSdKSdxscC7sU1F6uPtV1aUTGIT5PZYxEc_q2PqDtO9v1HPV93hxYMomTvrhAS7MXUivVDHxQqHQ$>

[A button with "Hear my name" text for name playback in email signature]<https://urldefense.com/v3/__https://www.name-coach.com/talya-levitz__;!!Mih3wA!Ap0nBboRSdKSdxscC7sU1F6uPtV1aUTGIT5PZYxEc_q2PqDtO9v1HPV93hxYMomTvrhAS7MXUivVaiweBWU$>

On Tue, Oct 7, 2025 at 7:50 PM Daniel Asarnow <dasarnow at gmail.com<mailto:dasarnow at gmail.com>> wrote:
Hi Talya,
Recently (~1 hour) discharged grids have always worked for me, as long as I observe the glow did take place. However I at times suspect that ambient humidity is affecting how long my grids remain hydrophilic, as compared to my previous lab. Could a time component explain what you're seeing?

Personally I only clean my grid blocks if there is something on them (e.g. plastic residue after chloroform washing), or if I am sterilizing them because the grids will be used in cell culture. Based on my observations the mode for other users is "never"...and many people glow discharge on the same parafilm-wrapped glass slide for years and years. Ethanol, isopropanol, acetone, or chloroform all seem like reasonable solvents to me, depending what might be on the block.

I also doubt if a long 20 mA glow is expected to destroy a quantifoil film. I usually do 15 mA for 45 seconds and observe no significant damage even if the grids are processed multiple times. But I haven't tried to go all out...

Best,
-da

On Tue, Oct 7, 2025 at 8:45 AM Talya Levitz via 3dem <3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>> wrote:
Hi all,

We are troubleshooting an issue where our glow discharger(s) seem to be of variable efficiency (sometimes making carbon grids appropriately hydrophilic, sometimes less so, occasionally not at all). My current theory is that the ambient humidity of the room is affecting the efficiency of the glow discharge. Has anyone encountered this or looked into it more thoroughly, and if so, what was your fix (account for humidity in timing / current? move the glow discharger into a more humidity-controlled room? desiccate the air going back into the chamber... somehow?). Other variables that have been ruled out are a faulty glow discharger, location of grid in the metal block, and whether it is the first glow of the day / session.

We regularly have >50% humidity in the room during the summer, even with the dehumidifier running at full speed, because of air flow etc. variables in the room that we cannot change. We have two glow dischargers, a Pelco Easiglo and a Quorum/EMS GloQube, and have seen this with both dischargers, although we use the GloQube more so we have seen it more with that. At one point I tried to blow all the carbon off a grid with a very prolonged (5 min @ 20 mA) glow discharge on the GloQube, and all the carbon was still entirely intact, which made me a bit nervous.

Relatedly, how often and how do you all clean your metal blocks that grids glow discharge on? We were thinking of using acetone and/or alcohol, but would appreciate recommendations!

Talya Levitz, PhD
Scientist I
talya_levitz at dfci.harvard.edu<mailto:talya_levitz at dfci.harvard.edu>
Pronouns: they/she
_______________________________________________
3dem mailing list
3dem at ncmir.ucsd.edu<mailto:3dem at ncmir.ucsd.edu>
https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem <https://urldefense.com/v3/__https://mail.ncmir.ucsd.edu/mailman/listinfo/3dem__;!!GNU8KkXDZlD12Q!75pQE7ReU3Wlg341-XTOq_oHuYVDnK97mRMoroSXJlUigM5sj-fUQIsbQjp7r6Eq4HXs-TcThek-ztVe$>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.ncmir.ucsd.edu/pipermail/3dem/attachments/20251008/f8b6a694/attachment-0001.html>