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Ruthenium Counterstain

Posted: Thu Mar 22, 2018 3:30 pm
by RaulCatena
Since a few people have asked, I think it is worth putting the word out on this. We recently published a method for counterstaining in IMC. It is an equivalent to Eosin in classic histology, and together with Iridium gives a very good H&E approximation (Which we call I&R).

Check out the paper here (



Re: Ruthenium Counterstain

Posted: Wed Aug 07, 2019 12:47 am
by mhadji

We've been using RuO4 on and off, but I've been having issues storing the 0.5% stock after opening the glass ampule.
I tried aliquoting in PCR tubes and freezing at -20, but the tubes became dark over time and the effectiveness of RuO4 was severely impacted.

I read online that for electon microscopy, people aliquot RuO4 in glass vials and store it at -80C, or even lower, to avoid loss of activity and RuO4 corrosive effects on plastic.
How does your lab store the RuO4 stock after opening?


Re: Ruthenium Counterstain

Posted: Wed Aug 07, 2019 4:48 pm
by RaulCatena
In deed is as you say.

We describe aliquoting of Ruthenium in glass vials in a previous manuscript where we used RuO4 for a different purpose ( ... to.a.22848). We should have, in fact, described this in the counterstaining article. Thanks for the heads-up to everybody.

Tipically I would aliquot an ampula in ~100 glass vials with a few micrometers each (~50 I believe) and freeze them all at -20C. Then vials would be used no more than 2/3 times. Usually thawed on ice, quickly used and froze down again.

This way, an ampula would last for more than a year, staining is good, no oxidation occurs, and operation is safer :)



Re: Ruthenium Counterstain

Posted: Thu Aug 08, 2019 12:10 am
by mhadji
Thank you