Posted by
Keith Morris on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Oil-in-a-10x-objective-tp2545827p2556384.html
I've had a few air objectives need to go back to Zeiss for 'repair', but
generally it always seems to be cell culture fluid or similar, and that's
nasty when it dries up on internal optics - most of our microscopes are
inverted and so will be at greater risk [gravity].
Non drying immersion oil has just crept into our Zeiss 40x Plan Neofluar top
lens but at the moment it images OK, but Zeiss say it's not economical to
repair, i.e. it's a lot more than the ~60% [of new] cost of repairs I paid
last-time, about 4 years ago.
I've never decided whether it's better to fully clean the oil objective
before storage - do you let the oil or the solvents do the damage? I tend to
never solvent clean the oil off if it's in frequent use. [manufacturers do
at least test the oil for safe use on objectives]. Given the deep scratches
the users leave on the objectives it probably doesn't matter either way.
Although oil creeps downwards [and upwards] I doubt it could make it to the
back of the objective [assuming its top's been wiped]. In my experience it's
temporarily resting the objective on a desktop that's contaminated with oil
[users get it everywhere] that does that. You often can't see the spilt oil.
I always put folded tissue down if I have to rest the objective somewhere,
but mostly I try to keep it my hand and put it straight into it's plastic
'tube' [to avoid the oil contamination - tried it once, didn't like it].
Pushing down the sprung top of the oil objective can push oil past the o
ring seal from where it can creep downwards unseen on the inner tube [not
into the internal objective optics, but it can drip into the microscope body
underneath [a problem with inverted microscopes]. So I advise users to avoid
pushing the oil objective top down.
Carefully apply the single small immersion oil drop to the objective lens
never the slide, particularly with inverted microscopes.
Once the 'liquid's' inside an objective you can't do much about it, other
than get more liquid inside when 'cleaning'.
This does remind to replace my Cargille DF oil, it's been open over 4 years
and we should have replaced after 2.5 years. It's that oil acidity again.
Keith
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Dr Keith J. Morris,
Molecular Cytogenetics and Microscopy Core,
Laboratory 00/069 and 00/070,
The Wellcome Trust Centre for Human Genetics,
Roosevelt Drive,
Oxford OX3 7BN,
United Kingdom.
Telephone: +44 (0)1865 287568
Email:
[hidden email]
Web-pages:
http://www.well.ox.ac.uk/cytogenetics/
-----Original Message-----
From: Confocal Microscopy List [mailto:
[hidden email]] On
Behalf Of Steven Ruzin
Sent: 27 March 2009 18:57
To:
[hidden email]
Subject: Re: Oil in a 10x objective
>Are you sure it's oil and not some other fluid? Either way, send the
>lens in for servicing, don't try to clean it yourself.
>
Not sure, but it probably is.
I wouldn't try to clean it myself.
--
____________________________________________________________________________
Steven E. Ruzin, Ph.D.
Director, Biological Imaging Facility
381 Koshland Hall College of Natural Resources
University of California Berkeley CA 94720-3102
510-642-6602 510-642-4995
(fax)
http://microscopy.berkeley.edu