Storing and re-using slides

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MichaelBrock
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Storing and re-using slides

#1 Post by MichaelBrock » Thu Nov 01, 2018 4:04 pm

I use new cleaned slides when making permanent mounts but I do quite a lot of spot-checking of diatom washes, bits of mystery particles around the house, algae, etc. So I tend to re-use those slides and cove slips. When I first started out (which wasn't very long ago) I came across a recommendation to store slides in a mixture of various liquids between uses. I made that mixture and use it to great effect. The slides come out and wipe off very clean. Unfortunately, I can no longer find where I found that recommendation (it might have been on Facebook and searching there is completely useless) and failed to write it down. I think it was distilled/ro water, alcohol, hydrogen peroxide and a touch of dish soap. Does this sound familiar to anyone?

Bryan
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Re: Storing and re-using slides

#2 Post by Bryan » Thu Nov 01, 2018 5:28 pm

I don't think it's safe to mix an oxidizer with a flammable liquid, be careful with that. I can see where the dish soap would help prevent drying spots. Kodak makes a product called Photo-Flo 200 that I use to prevent spots when drying photographic film, a small amount works really well. Mix it with distilled water.

https://www.bhphotovideo.com/c/product/ ... ution.html

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mrsonchus
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Re: Storing and re-using slides

#3 Post by mrsonchus » Thu Nov 01, 2018 5:30 pm

How about dishwasher rinse-aid?
John B

Bryan
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Re: Storing and re-using slides

#4 Post by Bryan » Thu Nov 01, 2018 5:33 pm

Incompatible hazardous materials.

Chemical: oxidizers (chlorine laundry bleach, hydrogen peroxide, calcium hypochlorite)

Don't Mix With: petroleum-based materials, fuels, solvents, corrosives, heat

Because: fire hazard, toxic gas generation

https://rmehs.fullerton.edu/_documents/ ... erials.pdf

MichaelBrock
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Re: Storing and re-using slides

#5 Post by MichaelBrock » Thu Nov 01, 2018 6:03 pm

Thanks for the replies. I didn't mean to suggest mixing those particular liquids. Just a vague memory of ingredients....hence my asking here :D

MicroBob
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Re: Storing and re-using slides

#6 Post by MicroBob » Thu Nov 01, 2018 8:45 pm

Glass surfaces can degrade as time goes by, depending on the type of glass. As far as I know it is not ideal to store slides long term in their cardboard box. Individually wrapped in paper is said to be better. Together with old microscopes I frequently got slides that were a couple of decades old - most of them were impossible to get into a usable condition again.

MichaelBrock
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Re: Storing and re-using slides

#7 Post by MichaelBrock » Sat Nov 10, 2018 1:09 pm

Someone on the Amateur Microscopy group on Facebook remembered the post:

Equal parts isopropyl alcohol (70%), peroxide, and a drop of dish washing liquid.

Hobbyst46
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Re: Storing and re-using slides

#8 Post by Hobbyst46 » Sat Nov 10, 2018 2:09 pm

MichaelBrock wrote:Someone on the Amateur Microscopy group on Facebook remembered the post:

Equal parts isopropyl alcohol (70%), peroxide, and a drop of dish washing liquid.
Hopefully he/she is still doing microscopy and posting... I am with Bryan's warnings (above) against mixing peroxide with flammable organic solvents like IPA (although it contains 30% water). It is not good practice. Moreover, peroxides degrade and lose their oxidizer power over time, so not of much value for long-term preservation of slides.
Zeiss Standard GFL+Canon EOS-M10, Olympus VMZ stereo

desertrat
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Re: Storing and re-using slides

#9 Post by desertrat » Sun Nov 11, 2018 2:03 am

Concentrated hydrogen peroxide would be very dangerous to mix with alcohol or any flammable liquid. However, the 2% or 3% hydrogen peroxide sold in supermarkets or drug stores isn't strong enough to do much worse than fizz a lot if mixed with something that decomposes it.

I believe these weak peroxide solutions can be mixed with alcohol with some water and no real reaction will take place. Tomorrow I'll mix some 3% peroxide with 70% ethyl rubbing alcohol (yes, that exists and some local drugstores sell it), and let you all know what happened.
Rick

A/O 10 Series Microstar
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MicroBob
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Re: Storing and re-using slides

#10 Post by MicroBob » Sun Nov 11, 2018 4:38 pm

Slides, and to a lesser amount cover slips, tend to deteriorate with time.

Birger Neuhaus scraped the topic on pages 29 and 30 of this book:
https://www.google.com/url?sa=t&rct=j&q ... kieDHLbA87

So idealy slides schould be stored in a way that this problem doesn't occur. I have searched the internet but have come up only with a superficial explanation of the problem and no ready solution at all. :(
The good news is that Birger will try to look further into this problem area and hopefully comes up with a recipe for proper slide storage.

I my self occasionally buy a nice older microscope (1950s onwards) and often there is a pack of slides and coverslips included. I rarely find these slides to be in usable condition - I can't get them clean any more.
Have you experienced this problem too?

desertrat
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Re: Storing and re-using slides

#11 Post by desertrat » Sun Nov 11, 2018 4:55 pm

MicroBob wrote:Slides, and to a lesser amount cover slips, tend to deteriorate with time.

Birger Neuhaus scraped the topic on pages 29 and 30 of this book:
https://www.google.com/url?sa=t&rct=j&q ... kieDHLbA87

So idealy slides schould be stored in a way that this problem doesn't occur. I have searched the internet but have come up only with a superficial explanation of the problem and no ready solution at all. :(
The good news is that Birger will try to look further into this problem area and hopefully comes up with a recipe for proper slide storage.

I my self occasionally buy a nice older microscope (1950s onwards) and often there is a pack of slides and coverslips included. I rarely find these slides to be in usable condition - I can't get them clean any more.
Have you experienced this problem too?
I've had good luck cleaning old deteriorated slides with dilute vinegar. These slides were difficult to pry apart and were covered with a thin whitish layer and small clumps of white powdery substance. I'm guessing these deposits were alkaline in nature, and the dilute vinegar dissolved them completely. What was left behind was a thin tarnish that looked in reflected light like coatings on lenses, but uneven. The slides appeared completely clear and clean by transmitted light. What might be clean enough for me might be different than your requirements. I find these old slides work fine for wet mounts of microscopic pond life. I would not use them for prepared slides to be sold.

However, I don't know if what is on your old deteriorated slides can be cleaned with vinegar, but might be worth a try.
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

desertrat
Posts: 243
Joined: Thu Apr 05, 2018 1:06 am
Location: Idaho

Re: Storing and re-using slides

#12 Post by desertrat » Mon Nov 12, 2018 3:00 am

This morning I mixed a few milliliters of 3% hydrogen peroxide and 70% ethyl rubbing alcohol, roughly equal amounts, in a test tube.

The combined mixture would be about 35% ethanol and 1.5% hydrogen peroxide. There was no visible reaction, although holding the test tube up to a window, faint lines of uneven refractive index could be seen, probably resulting from incomplete mixing. After a little more mixing the lines disappeared. After a few minutes, the mixture seemed to be just a bit warmer than the starting liquids. That could have been heat released from the two liquids going into mutual solution instead of heat from a reaction. No real way to tell, however.

A short time later some very tiny bubbles formed in the solution which eventually floated to the surface. These may have been oxygen bubbles formed when a little of the peroxide decomposed due to impurities in the solution.

After several hours there were no further signs of any reaction, although the aroma of the solution changed from the characteristic odor of denatured ethanol to something a bit different. An old cork was inserted very lightly into the test tube to keep dust out, and it might have carried over some odor of other organic liquids from previous uses.

A solution like this should probably be made up in just enough quantity for the use at hand, and then discarded.

That said, I would not be tempted to mix 35% hydrogen peroxide with any organic liquid, but I think 2% or 3% is pretty safe, unless the other liquid is highly reactive.
Rick

A/O 10 Series Microstar
A/O 4 Series Microstar
A/O 4 Series Phasestar
A/O 4 Series Apostar
A/O Cycloptic Stereo
Several old monocular scopes in more or less decrepit but usable condition

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