Use of oil immersion objective with live samples

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tlansing
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Use of oil immersion objective with live samples

#1 Post by tlansing » Thu Dec 17, 2020 11:29 am

I have to admit that I have been intimidated to use my 100x oil immersion objective to observe live specimens (I have used them extensively for permanent slides). I would appreciate any advice the users of this forum can provide concerning this topic, including any considerations for setting up wet samples, appropriate oil to use, etc. Thanks in advance for your help and advice.

MicroBob
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Re: Use of oil immersion objective with live samples

#2 Post by MicroBob » Thu Dec 17, 2020 4:33 pm

Hi Tim,
this can be done without much problem when considering a couple of things:
- Use a fairly big cover slip, e.g. 20x20
- For the standard biological microscope use the thinner viscosity of immersion oils, not the thicker flowing one for inverted microscopes
- Use thin water layer so avoid sand and bigger particles under the cover slip
- Don't release you catch back in your pond aquarium

I attatch the cover slip with a strip of Tesa tape so most sits on the slide and only a 3mm is on the cover slip. Then it works even when I don't stick to the first the rules! :lol:
With fast moving plancton animals it is difficult to keep them in focus with the 100:1 objective. So have a dry objective with generous free working distance next to it so it doen't dip in the oil or use a low power oil objective, I have a Leitz 22:1 for this use.

Bob

tlansing
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Re: Use of oil immersion objective with live samples

#3 Post by tlansing » Thu Dec 17, 2020 10:31 pm

Thanks for the helpful information!

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KurtM
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Re: Use of oil immersion objective with live samples

#4 Post by KurtM » Fri Dec 18, 2020 12:47 am

For those who do lots of wet mounts, try using 22 x 50 mm cover slips. The greatly increased area makes using immersion oil easier, and reduces sample dry-out.
Cheers,
Kurt Maurer
League City, Texas
email: ngc704(at)aol(dot)com
https://www.flickr.com/photos/67904872@ ... 912223623/

tlansing
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Re: Use of oil immersion objective with live samples

#5 Post by tlansing » Fri Dec 18, 2020 1:38 am

Hi Kurt,

What do you mean by easier?

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KurtM
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Re: Use of oil immersion objective with live samples

#6 Post by KurtM » Sat Dec 19, 2020 1:30 am

Easier in that there's much more cover slip to work with, so you get a bigger target area.
Cheers,
Kurt Maurer
League City, Texas
email: ngc704(at)aol(dot)com
https://www.flickr.com/photos/67904872@ ... 912223623/

DonSchaeffer
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Re: Use of oil immersion objective with live samples

#7 Post by DonSchaeffer » Sat Dec 19, 2020 10:24 am

can you get the larger cover glass in thinner thickness?

hans
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Re: Use of oil immersion objective with live samples

#8 Post by hans » Sat Dec 19, 2020 8:13 pm

DonSchaeffer wrote:
Sat Dec 19, 2020 10:24 am
can you get the larger cover glass in thinner thickness?
Another nice thing about the larger 22/24 x 40/50 mm sizes is that there is a lot of lab surplus in 10 oz. cases on eBay, for example:
#1.5 thickness: https://www.ebay.com/itm/331552074930
#1 thickness: https://www.ebay.com/itm/293034123609

Sometimes even cheaper making offers on old/obscure listings.

DonSchaeffer
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Re: Use of oil immersion objective with live samples

#9 Post by DonSchaeffer » Sat Dec 19, 2020 10:26 pm

Thanks. I have the smaller #1 coverglasses for live specimens. I have a lot of them. These do seem a bit pricey--with the postage.

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