Bubbles, bubbles, bubbles...

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pippo1234
Posts: 81
Joined: Thu Dec 24, 2020 8:21 am

Bubbles, bubbles, bubbles...

#1 Post by pippo1234 » Sun Mar 07, 2021 8:45 am

I am relatively new to making slides. I have read quit a bit and watched quite a few videos around on how to minimise air bubbles between the coverslip and slide.I understand that you have to lower the coverslip as slowly as you can starting from it touching the slide on just one side, but that seems a necessary though not sufficient condition... I'd appreciate any advice on how to improve on that. My mounts are not terrible by now, but still have more bubbles than I'd like. I'd appreciate any advice.

The following is a list of "refeniments" on the basic process I have read about.

1. Put a cover slip on the specimen with no mountant. Use a pipette to put a drop of mountant at the corner of the slide so that it gets sucked under the coverslip by capillary action.
2. Put the specimen on a coverslip with a drop of mountant on top. Lower the slide onto it.
3. Put the specimen on a coverslip with a drop of mountant on top. Tilt the coverslip onto a warmed slide (for glycerin and similar mounts. Source: Peacock's Elementary Microtechnique).
4. Warm up the slide gently to eliminate bubbles (again Peacock as well as Brunel Microscope video on mounting pollen).

My confusion/doubts are the following (numbering corresponding to the above):

1. It seems to me it works only with wet mounts, but for many of them (e.g. protozoa) the specimen is inside the mounting medium (water). I cannot see how it works for pollen either since pollen cannot be mounted in water.
2. I have tried it and end up with signficantly more bubbles than if I lower the coverslip onto the slide.
3. The mountant runs in the process and you completely lose control of the placement of the specimen.
4. I have used it with gelatin jelly mounts but have not been able to make it work with bubbles other than at the very edge of the coverslip. If the temperature is high enough (50-60, I am using a coffee warmer) bubbles do move rather quickly towards the edge but new ones form too. Basically, it looks as if the mountant is close to boiling.

Thank you very much in advance.

Giulio

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mrsonchus
Posts: 4175
Joined: Tue Feb 03, 2015 9:42 pm
Location: Cumbria, UK

Re: Bubbles, bubbles, bubbles...

#2 Post by mrsonchus » Sun Mar 07, 2021 10:55 am

Hi, what are you mounting and what mountant are you using?
John B

pippo1234
Posts: 81
Joined: Thu Dec 24, 2020 8:21 am

Re: Bubbles, bubbles, bubbles...

#3 Post by pippo1234 » Sun Mar 07, 2021 11:12 am

For long-term mounting, I use PVA-G or glycerin jelly. The aim is to mount all kind of stuff. At the moment pollen and insect parts, but would like to mount plant sections as well if the quality is worth it (which goes back to our microtome discussion).

I seem to get more bubbles when wet, water-based, mounting than with long-term mounting.

Peter
Posts: 226
Joined: Sun Oct 12, 2014 5:34 pm

Re: Bubbles, bubbles, bubbles...

#4 Post by Peter » Mon Mar 08, 2021 5:53 pm

Hi Giulio,
I just hold the coverslip over the specimen and drop it, never seen this method recommended but it works for me with few bubbles.
Peter.

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