Cover Slip Issues with Euparal

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KC2EP
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Cover Slip Issues with Euparal

#1 Post by KC2EP » Tue Oct 06, 2020 3:47 pm

Good Day All!
I am new to creating permanent slides with whole mount insects as I mostly do fungal spore mounts, wet mounts, and air sample analysis. I have recently purchased some Euparal and attempted to prepare slides of a tick, an insect exoskeleton found on my basil plants, and some random Diptera. I cannot get the cover slip to sit remotely flat and the mounting medium migrates away from the cover slip. Youtube is not being much of help in this area. Any suggestions? I did not yet process the specimen in KOH, but it has been stored in 95% ETOH.

BramHuntingNematodes
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Re: Cover Slip Issues with Euparal

#2 Post by BramHuntingNematodes » Tue Oct 06, 2020 3:58 pm

well you know ticks are kind of thick and the hempstead halide euparal is pretty thin Gray suggests either using squares of celluloid to support the coverslip or to employ a cell which is a support that completely surrounds the subject while supporting the cover slip. it is mounted to the slide beforehand with adhesive not soluble in whatever you're using to mount to specimen. I think some expediencies such as using the trusty nail polish to draw a ring around the center before mounting the specimen have also been suggested.
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination

KC2EP
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Re: Cover Slip Issues with Euparal

#3 Post by KC2EP » Tue Oct 06, 2020 8:01 pm

That makes sense. I was trying to get away from ringing the slides, but if it works, it works. Thanks.

EYE C U
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Re: Cover Slip Issues with Euparal

#4 Post by EYE C U » Tue Oct 06, 2020 9:33 pm

I bought some of this stuff..it stinks..in both meanings

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mrsonchus
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Re: Cover Slip Issues with Euparal

#5 Post by mrsonchus » Tue Oct 06, 2020 10:20 pm

I cut coverslips for spacers with Dremmel mini diamond-dust covered tools, used as a scribe like a glass cutter...
The diamond-dust covered Dremmel mini-tool thingies,
Image

Quite tidy coverslip-spacer pieces cut,
Image

Placed around thick specimen in slide,
Image

Easier than it looks.... Used to mount in resin-based mountant no sealing needed either...

I mounted these stained hand sections (horribly thick!) with this method back in July - using a resinous mountant 'Histomount', which I use for my regular microtome-cut slide-making. The coverslip spaces are in place and the mounts are at least very long-term if not permanent....
Image

Here the spacers are visible....
Image

and,
Image

This is pretty easy to do with the Dremmel bits as glass scoring tools for cutting the coverslips... Same method for Euparal shoul be fine....
John B

KC2EP
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Re: Cover Slip Issues with Euparal

#6 Post by KC2EP » Wed Oct 07, 2020 1:21 am

Great Idea! I'll give that a try!

MicroBob
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Re: Cover Slip Issues with Euparal

#7 Post by MicroBob » Wed Oct 07, 2020 8:12 am

Euparal contains a lot of solvent that gasses out sooner or later. So when you prepare a nice slide of a sturdy thicker specimen the solvent will evaporate and air pockets will move under the cover slip, finally taking up half the area. You can counter this by adding more Euparal and then even more when this gives of it's solvent too.
I haven't tried this, but it might work:
- Put specimen on cover slip
- Add Euparal
- Let solvent gass out
- Add more Euparal
- Let solvent gass out
- Add a little more Euparal
- Pick up the cover slip with a slide
- Add Euparal from the sides as the last layer dries

This way cou could get rid of much of the solvent before assembling coverslip and slide.

A good semi-permanent mountant for insects: Hoyers medium. If you can get hold of the chlo... you better don't mess with Gummi arabicum (often questionable quality) but use "Gutenberg Gummierstift" a classic paper glue that is made of good quality Gummi arabicum.

Bob

MichaelG.
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Re: Cover Slip Issues with Euparal

#8 Post by MichaelG. » Wed Oct 07, 2020 9:57 am

MicroBob wrote:
Wed Oct 07, 2020 8:12 am
... you better don't mess with Gummi arabicum (often questionable quality) but use "Gutenberg Gummierstift" a classic paper glue that is made of good quality Gummi arabicum.
Thanks for that information, Bob
https://www.manufactum.co.uk/gutenberg- ... er-a10576/

I note that they only claim two years ‘stick’ life
... is that your experience ?

MichaelG.
Too many 'projects'

MicroBob
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Re: Cover Slip Issues with Euparal

#9 Post by MicroBob » Thu Oct 08, 2020 8:34 am

Hi Michael,
after a recommendation by an experienced microscopist I mixed Hoyers mix from Gutenbergs glue but haven't used it so far. Problems with the quality of the available Gummi arabicum are well known. Hoyer's medium is generally only seen as semi-permanent, in many (but not all, would be too simple!) cases it starts to crystalize after halt a year or a year. But some people don't really have problems with it so it may be a question of the individual mountant and handling. The stated sticking time probably applies more to a situation where paper is glued, not to our situation with the mountant enclosed under the cover slip.

This article might be interesting for you:
https://www.biotaxa.org/Zootaxa/article ... a.4322.1.1
It is about long term longevity of mountants.

Bob

MichaelG.
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Re: Cover Slip Issues with Euparal

#10 Post by MichaelG. » Thu Oct 08, 2020 8:42 am

Many thanks, Bob

MichaelG.
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Microworld Steve
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Re: Cover Slip Issues with Euparal

#11 Post by Microworld Steve » Tue Oct 27, 2020 5:17 am

KC2EP, are you a ham operator? KC2EP is a ham call sign and I looked it up on QRZ.com. My call is KM4JZJ. :D
If I can't see it with my microscope, it ain't worth looking at. :D

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