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PostPosted: Tue Aug 13, 2019 9:10 am 
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Location: Cumbria, UK
Roldorf wrote:
Just prepared a fructose slide without soaking in alcohol.


Hi Roldorf, an interesting thread!

The 'soaking in alcohol' part is really either to dehydrate a specimen, as part of a series of treatments ultimately ending with a totally water-free mountant, or as a quick 'killing' stage. For embedding & mounting in fructose (I also made some fructose mounts when I was followingthrough WD's work when I started) the process is 'water-based' it may be said, and doesn't require the use of alcohol.

What you could do is put your sample through say 50% then 75% alcohol to fix the tissue, then reverse the procedure back to water, which will correct the reversible effects of plasmolysis, before proceeding to sugar....

Looking forward to seeing the next result.

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PostPosted: Tue Aug 13, 2019 9:44 am 
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MicroBob wrote:
...When making jam 50% fructose content is said to be not enough as the only conservative, contrary to normal sugar. I don't know how much this improves towards higher fructose contents in the mountant.
Hi Bob,
the fructose solution I use is ~80%. It was NOT prepared from sterile components under aseptic conditions. It is stored in the room for over a year, and visibly is not changed or attacked by organisms.

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PostPosted: Tue Aug 13, 2019 10:00 am 
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Hobbyst46

How did you determine when it was at 80%? I just kept dissolving it until I couldn't dissolve any more and I must admit that I now have lots of crystals showing up in the mixture that I put into the bottle. Maybe I should add a little water and give it a good shake.

I have had a look at the earlier mounts I did with just nail polish. The polish seems to be shrinking and exposing the sample as I now have lots of voids which were not there when I first made the slide.

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Bresser Science Infinity 4x 10x 40x 60x 100x oil. Canon EOS 4000d


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PostPosted: Tue Aug 13, 2019 10:34 am 
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Roldorf wrote:
Hobbyst46
How did you determine when it was at 80%? I just kept dissolving it until I couldn't dissolve any more and I must admit that I now have lots of crystals showing up in the mixture that I put into the bottle. Maybe I should add a little water and give it a good shake.

I prepared it by weight. Weigh out the amount of fructose (say, 20g) into a heat-resistant glass jar. Add distilled water (say, 5g = 5ccm = 5ml). Stopper the jar lightly. Place the jar in a small pot of water, such that the jar is immersed but not floating, and support the jar to prevent overturn. Verify that the lid of the jar fits loosely, not hermetical sealing. Heat the pot to boiling. Let it stand like this for a while. Most or all of the fructose will dissolve. Let it cool down. If there are still crystals, can add water dropwise.

It is possible to verify the final concentration by its refractive index, or alternatively its density, or its viscosity. The first one requires a refractometer. The second one - a sensitive balance (say, sensitivity of 0.01g). The third one - a very tall glass jar and tiny balls of known density, and a constant temperature ambient space. Neither option is easy under hobby conditions!

So, I would suggest that you simply do the following: heat your fructose solution as described above; bring to complete dissolution by adding DW dropwise. Let cool. If the result is a clear viscous liquid, use it. If it is turbid contains grains, filter through a coarse filter paper or even a nylon hose.
Quote:
I have had a look at the earlier mounts I did with just nail polish. The polish seems to be shrinking and exposing the sample as I now have lots of voids which were not there when I first made the slide.
Nail polish contains volatile chemicals, of the acetone family. When it dries out too quickly, they evaporate, perhaps this is what happened to your sample. When mounting with nail polish, immediately seal the coverslip around with nail polish as well.

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PostPosted: Tue Aug 13, 2019 11:02 am 
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Ok that explains it. I didn't seal around the cover-slip with the nail varnish.

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Bresser Science Infinity 4x 10x 40x 60x 100x oil. Canon EOS 4000d


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PostPosted: Tue Aug 13, 2019 11:17 am 
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Hi Doron,
may be the sugars differ in how well they conserve the fruit content, not themselves.
Fructose tends to attract humudity - this might help here to avoid that it dries out completely.

@Alan: With nail polish it might help to:
1. thin layer of nail polish on cover slip
2. apply sample from Acetone or nail polish remover (has to water-dry before)
3. apply nail polish on coverslip and sample
4. Let evaporate part of the nail polish to minimize shrinking
5. apply nail polish on slide and pick up the cover slip with the slide

To test nail polish as a mountant it might be helpful to use flat, dry samples from the beginning to eliminate the drying step.

I tested UV glue and paint for artificial finger nails too. It doesn't adhere well to the glass and tends to pop off.

As a widely available mountant for water free samples I would like to suggest LOCA TP 2500 (ebay). This is UV-glue to glue glass screens on smartphone display. I used with for radiolaria with great results. It cures with UV light and doesn't shrink.



Bob


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PostPosted: Tue Aug 13, 2019 12:01 pm 
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Ok. No alcohol Fructose sealed with nail polish.

I will definitely try to thin the Fructose Mix with a little water.

Image

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Bresser Science Infinity 4x 10x 40x 60x 100x oil. Canon EOS 4000d


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PostPosted: Tue Aug 13, 2019 12:10 pm 
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Roldorf wrote:
Ok. No alcohol Fructose sealed with nail polish. I will definitely try to thin the Fructose Mix with a little water.
The result looks nice IMO, better than the previous ones. I would keep it and inspect every 3 months or so.

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PostPosted: Tue Aug 13, 2019 6:47 pm 
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Progress Alan. :)

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