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static during weighing of standards

Posted: Wed Apr 25, 2018 3:07 pm
by MestizoJoe
Hello. An in-house qualified standard has a lot of static. Material jumps off the spatula and sticks to drying dish walls.

Can anyone provide tips on how to handle this problem?

I have found that not wearing nitrile gloves helps. Using a static gun does not make a noticeable difference.

This standard is transferred from the storage bottle (Polypropylene) to a drying dish (glass) and dried at 105C in an oven. Then weighed into a plastic weigh boat. Static is a problem throughout these steps.

Thanks!

Re: static during weighing of standards

Posted: Wed Apr 25, 2018 7:45 pm
by James_Ball
Stored in a glass bottle may help.

One thing we did in the past was to tape a dryer sheet (Downy, Bounce, Snuggle, ect) to the back wall of the balance enclosure to reduce static. It worked pretty well. Another is to make a dilute solution of fabric softener in a spray bottle and spray down the area, but that can lead to cross contamination depending on the target of interest.

Re: static during weighing of standards

Posted: Wed Apr 25, 2018 9:39 pm
by Zoraku
James_Ball wrote:
Stored in a glass bottle may help.

One thing we did in the past was to tape a dryer sheet (Downy, Bounce, Snuggle, ect) to the back wall of the balance enclosure to reduce static. It worked pretty well. Another is to make a dilute solution of fabric softener in a spray bottle and spray down the area, but that can lead to cross contamination depending on the target of interest.



I second the recommendation of storing in a glass bottle. I work with a number of granular products that our formulation lab used to provide me in a plastic polymer bottle - tons of static.

I requested glass jars instead and this significantly reduced the amount of static.

I might also suggest weighing into an aluminum weigh boat instead of a plastic weigh boat.

Re: static during weighing of standards

Posted: Thu Apr 26, 2018 7:44 am
by Peter Apps
As far as possible use metal containers and utensils.

Peter

Re: static during weighing of standards

Posted: Thu Apr 26, 2018 9:00 am
by lmh
you've reminded me that I want to have a Word with Sigma chemicals about supplying 25mg of highly static white powder in a white conical plastic insert in a white bottle. Inside the container the material is completely invisible; the first glimpse the customer gets is as it whizzes off the spatula and sticks itself to the left-over plastic foamy stuff on the rim of the container, the foamy stuff they use to seal the tops of pots.

Nothing like paying a total fortune for a miniscule amount of a beautifully clean standard, which has no doubt taken someone weeks to make, only to have the whole process messed up by the packaging.

Re: static during weighing of standards

Posted: Thu May 03, 2018 11:55 pm
by LALman
Whatever happened to use of those Polonium emitter plates you could put in a balance cavity? I have a couple of them to dispose of that were in my balance untill I checked the expiration date. They expired back in ~2004.

I like the dryer sheet idea. We had one taped to the thermal tape output slot on an old model ICP-AES. Because static would build up and crash the CPU running the ICP. That was back in the 1980's

Re: static during weighing of standards

Posted: Thu May 24, 2018 3:09 pm
by dap
Hello. Don't use gloves.

Re: static during weighing of standards

Posted: Thu May 24, 2018 4:49 pm
by Zoraku
dap wrote:
Hello. Don't use gloves.


I fear that might not always be the best idea, especially when working with a concentrated or pure material that may or may not have significant harmful effects (carcinogenic, teratogenic, etc...)

Re: static during weighing of standards

Posted: Tue May 29, 2018 7:23 pm
by MMJ88
Po-210 emitters work great. The company NRD makes them as "Staticmaster", I use them in my lab for our very sensitive balances.

Re: static during weighing of standards

Posted: Tue May 29, 2018 7:44 pm
by LALman
Thanks for that info. I may replace mine now that I know where to get them.