MicrobeHunter.com Microscopy Forum

Hi Everyone
I have some solid canada balsam and am trying to see if ethyl alcohol is a suitable solvent, trying to avoid things like xylene... 100% alcohol seems to dissolve the crystals, but the solution is translucent yellow (not surprising), when placed on a glass slide, the solution dries and looks the same, but there is some cloudy precipitate (water from the environment? im not sure).
Anyways, i was curious, has anyone used commercial canada balsam? does it dry to be colourless?

Also, has anyone used any other solvents for balsam other than xylene? I think i saw someone mention limonene or acetone but didnt find much online.

Thanks!

Hi,
Canadabalsam is not a precisely defined substance so it will vary. Usually it is a little yellowish, which is not a problem in use. Ethanol is hygroscopic and the etanol thinned Canadabalsam will be cloudy because of the water. Orange peel oil might be usable but it is probably impossible to determine how long the slides will last. If you want to avoid xylene you might use Euparal which can be used out of isopropanol.

Bob

Hi Bob
sure that makes sense, i was hoping the canada balsam with alcohol could have alcohol dehydrated samples embedded directly.
If i can find a cheap source of citrus oil or limonene i might try, but then again, i dont need permanent slides that last for a century
Euparal is on my list along with neumount, i just want to find a vendor in north america, if not i will order from the EU

MicroBob wrote: ↑

Sun Jul 11, 2021 2:37 pm

Hi,
Canadabalsam is not a precisely defined substance so it will vary. Usually it is a little yellowish, which is not a problem in use. Ethanol is hygroscopic and the etanol thinned Canadabalsam will be cloudy because of the water. Orange peel oil might be usable but it is probably impossible to determine how long the slides will last. If you want to avoid xylene you might use Euparal which can be used out of isopropanol.

Bob

anhydrous ethanol is available

Some yellowing from exposure to air and light. It's slow.
Many years to creep in from the edges of an unsealed cover slip.

Ok, I left some overnight to set (i realize it takes a while), but will check when i get into the lab. I saw some archival photos which showed yellowing but i wasnt sdure if those were old slides, or recently prepared ones.
Regardless, I will try to find some euparal and prep slides .

The alcohol i was using was 100%, brand new sealed bottle. I realize there is humidity in the air, but the balsam was also kept uncovered (for some evaporation) in a -ve pressure fume hood, but sure, some water could be absorbed.

I have not had it completely clear. Seems a touch of yellow. I have not used it with anything other than xylol/ xylene. When I use it I incubate slides at 105 degrees f. for 5 or 6 days to get a good seal. Under cover glass balsam can remain liquid for years, so I like to heat set specimens when possible.
Greg