Keep Dry Diatom on slide

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Suphot
Posts: 99
Joined: Wed Mar 11, 2015 4:35 am

Keep Dry Diatom on slide

#1 Post by Suphot » Tue May 04, 2021 6:25 am

I saw some algae on water tray, so I sampling them on slide by wet mount. It contain some diatoms which I think it is good to keep it for a while.
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Suphot
Posts: 99
Joined: Wed Mar 11, 2015 4:35 am

Re: Keep Dry Diatom on slide

#2 Post by Suphot » Tue May 04, 2021 6:27 am

But cleaning and permanent mounting them is complicate and difficult, so I let it slowly dry under cover slip in the room.

After several day, I observe it under microscope, it is still looking OK. Some way some how, when it was dry up, algae and diatoms was fix on slide under cover slip.
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Suphot
Posts: 99
Joined: Wed Mar 11, 2015 4:35 am

Re: Keep Dry Diatom on slide

#3 Post by Suphot » Tue May 04, 2021 6:28 am

So I use thin strip of scotch tape to fix 4 sides of the cover slip to slide. I don’t know how long it can be kept in this way. I can store this slide with algae and diatom vertically in the slide box in the same way as permanent slide.
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Suphot
Posts: 99
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Re: Keep Dry Diatom on slide

#4 Post by Suphot » Tue May 04, 2021 6:29 am

Now it was more than 6 – 7 months, I still can observe diatoms sample in this slide. It look OK for me under 60X dry objective.
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Diatom 03.jpg
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Diatom 02.jpg
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Suphot
Posts: 99
Joined: Wed Mar 11, 2015 4:35 am

Re: Keep Dry Diatom on slide

#5 Post by Suphot » Tue May 04, 2021 6:31 am

But this is not for serious observation of diatoms, because diatoms was dry under cover slip which contain thin layer of air. So it is not give good result with 100X Oil objective.

I think it is a simple and easy way to keep diatoms sample for a while. It need not complicate process and high refractive index mounting medium. For amateur like myself, I think it is worth to keep it. How many years it can be keep in this way, time will tell.


Suphot.

Charles
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Re: Keep Dry Diatom on slide

#6 Post by Charles » Tue May 04, 2021 12:41 pm

For a simple fix, you could seal the edges with varnish or fingernail polish. That way, you wouldn't need the tape.

Hobbyst46
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Re: Keep Dry Diatom on slide

#7 Post by Hobbyst46 » Tue May 04, 2021 2:58 pm

Charles wrote:
Tue May 04, 2021 12:41 pm
For a simple fix, you could seal the edges with varnish or fingernail polish. That way, you wouldn't need the tape.
I do it stepwise: First, I put the smallest possible amount of nail polish or varnish around the coverslip, otherwise the sealant tends to crawl (by capillary) inside, under the coverslip. When it dries out (a mcouple of hours) I reinforce it with a second layer of varnish.

MicroBob
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Location: Northern Germany

Re: Keep Dry Diatom on slide

#8 Post by MicroBob » Tue May 04, 2021 3:02 pm

Hi Suphot,
nice and simple method! I think that most bacterial an fungal activity will take place in the first weeks so the slide should be more or less stable from now on. If you woulf like to go one step further you could clean the diatoms by incineration. I found it to be practical to put the cover slip on a 3-4mm stainless steel plate, heat from below with an alcohol burner to maybe 300-400 °C, the apply the flame on a blue flame lighter from above. This way most organic matter is burned off. The diatoms stick to the cover slip and can mounted in whatever. Air has an refractive index of 1,0 vs. the diatom's r.i. of about 1,45. This give a usable but a bit strong contrast.

Bob

Suphot
Posts: 99
Joined: Wed Mar 11, 2015 4:35 am

Re: Keep Dry Diatom on slide

#9 Post by Suphot » Wed May 05, 2021 3:14 pm

Thank you very much for all comments,

Charles;

I afraid to seal cover slip with vanish or finger nail polish because it may leak in to diatom and made it more difficult to see.


Hobbyst46,

Yes, it is difficult to avoid capillary effect, so I use scotch tape to fix cover slip in place.


MicroBob,

Thank you very much for your recommend technic, I will try it. It is easy to try. I am not fix it with high refractive index mountant. Beacuse it is expensive and I have not many type of diatoms to collect and fix.

Cheers,

Suphot.

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