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For a good discussion on microscope cleaning see:
http://micro.magnet.fsu.edu/primer/anatomy/cleaning.html
But then they pussyfoot around the issue as well - immersion oil damages
microscopes, solvents damage microscopes, cleaning damages microscopes, not
cleaning damages microscopes etc...all true I suppose. Molecular Expressions
seem to favour using bits of dead antelope [chamois leather] over 100%
cotton buds [just in case they have man-made fibres added], each to their
own.
Microscope engineers have been using ether for probably more than a hundred
years, and I've used it for 30 without any problems [although my 10ml will
evaporate from the bottle over the years before its used up, as its used so
sparingly]. My comments are really aimed at those of us that use oil
immersion objectives. Organic solvents shouldn't be used routinely on oil
immersion objectives either, perhaps a few times a year at best, and are
really a last resort when the objective is so dirty it's unusable. Removing
the immersion oil as part of a serious decontamination process should only
take a few seconds. I don't scrub, just touch the cotton bud on the lens
surface with a few gentle circular movements and then turn it over to the
other clean side and remove the solvent + oil.
That said soap and water removes major immersion oil spillages on our
removable glass slide holder stage-insert very effectively and whereas some
organic solvents would take the black paint off as well. One problem with
water based lens cleaners is if the stuff dries onto the glass, which can be
terminal for a lens [so I use ultra pure water, and OK a bit more ether to
ensure the waters removed fully, as alcohol is apparently less lens cement
friendly]. Unless the oil immersion objective has real contamination issues,
microscope tissues gently removing the excess of oil is all that is
required, day in day out. Our air objectives only require a air jet/blower
every now and then - no touching required [unless cross contaminated with
immersion oil]. If an objective seems to need a lot of cleaning, it's
probably damaged.
Most problems develop in multi-user facilities where oil and air objectives
are shared on an inverted microscope used for live cell imaging [for which
we tick all the boxes].
Regards
Keith
---------------------------------------------------------------------------
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: [log in to unmask]
Web-pages: http://www.well.ox.ac.uk/molecular-cytogenetics-and-microscopy
-----Original Message-----
From: Confocal Microscopy List [mailto:[log in to unmask]] On
Behalf Of Grant MacGregor
Sent: 21 March 2011 19:20
To: [log in to unmask]
Subject: Re: Cotton wool for lens cleaning
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I concur with Craig and Mark regarding use of ether and any other solvent of
lens cements. Many years ago I watched the front lens of a 1.4NA condenser
fall out following too much elbow grease with ether-soaked cotton buds /
Q-tips. Ether no more.
Several years ago someone dumped a plate full of tissue culture media down
the nosepiece of a shared facility's vert 200m I was in charge of
overseeing. Prior to fitting the aqua stop, I watched with great interest
to see what the extremely senior, German accented and fussy Zeiss field
service engineer would use to clean the optics. Would it be Opti L ? Would
it be pure ether ? Surprise surprise, he whipped out a large spray bottle
of Sparkle. This is a surfactant-laden ammonia free solution one can
purchase online or at an Ace Hardware (if in the US). The regular Sparkle
is purple. A while ago I suspect the makers of Sparkle found out that folks
were using it for high-end optics as they started packaging it in smaller
(c. 100ml) bottles and leaving out the purple dye. I don't know if they
charge more for this, but I would assume so. I discovered if you leave the
bottle of purple Sparkle in the window, the purple dye (presumably) oxidises
with a few weeks, becoming colorless.
For what it is worth, our general rule of thumb for cleaning optics is as
follows.
Try in order the following solvents - 1) distilled water; 2) Sparkle. If we
have to use Sparkle, we follow up with distilled water, which can be simply
applied by breathing on the optic.
Clean using only pure cotton or silk and not lens paper. I was taught that
lens paper should be used only for storage of optics. Back in the day,
microscope field engineers often wore silk ties that had a bunch of stains
on the back of them.
Clean in a circular manner in a single direction, taking care not to drag
any dirt back over the cleaned area.
Grant MacGregor
Developmental and Cell Biology,
UC Irvine
On Mar 17, 2011, at 12:04 PM, Craig Brideau wrote:
> *****
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> *****
>
> I agree with Mark. Acetone will eat any rubbers/sealers/epoxies holding
> your lens together. I only use acetone on mirrors out on the optical
bench
> that are held in place with friction mounts (i.e. no epoxy). For anything
> glued or sealed I use high-purity methanol and lens tissues.
>
> Craig
>
>
> On Thu, Mar 17, 2011 at 7:09 AM, Mark Cannell
<[log in to unmask]>wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> *****
>>
>> From direct experience, I urge a note of caution with acetone, you may
>> degrade the lens mounting glue and risk spreading it over the lens.
>>
>> Regards Mark
>>
>>
>> On 17/03/2011, at 12:40 PM, Cammer, Michael wrote:
>>
>> *****
>>> To join, leave or search the confocal microscopy listserv, go to:
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>>>
>>> I don't think there really is one general solvent. When I began doing
>>> biological microscopy about 20 years ago the immersion oils all seemed
to be
>>> made of the same stuff and easily cleaned with just about any organic
>>> solvent stronger than ethanol. This is no longer the case. For
instance,
>>> the new Nikon oil for TIRF gets thick and is completely impervious to
any of
>>> the aqueous cleaners. It is resistant to what we practically considered
to
>>> be the universal solvent of organics, acetone, and also to ethanol. But
>>> dehydrated methanol works great. On the other hand, the Zeiss oils,
when
>>> fresh, clean up fine with their aqueous cleaning solutions and when old
and
>>> dripped all over the turret and such, with acetone. The old standby in
the
>>> lab, Cargill Labs type DF, cleans up with any inorganic solvent. Of
course,
>>> in one lab the gospel was xylene because, well, we scientists tend to be
>>> superstitious or traditional. As for ether, one benefit of using it, we
>>> were told years ago by someone at Zeiss, is that it evaporates so fast
that
>>> it reduces the chances of dissolving the glue holding in the front glass
of
>>> the objective. Is this really a problem? I've never had one of these
front
>>> lenses come loose. Now I tend to use 1:1 acetone/methanol and cotton
swabs
>>> and/or lens tissue following in the footsteps of Spectraphysics service
who
>>> uses this to clean their mirrors and gives us average power of a Watt
with
>>> 100 fs pulses at 910-920 nm, so I follow by example.
>>> -Michael Cammer
>>>
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