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Good afternoon,
a comparatively simple method might be to actually measure the refractive
index, at least of the mounting medium, using an Abbé B refractometer.
Most institutes with a chemistry department will have one. It's a device,
which you can easily carry to your own lab, if you get it on loan.
The main problem with older Abbé refractometers is that they may be
limited to one wavelength, only. Other refractometers, which overcome this
problem, are of the Pulfrich or the Michelson type, though they are much
more cumbersome to use.
Best wishes,
Johannes Helm
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> To join, leave or search the confocal microscopy listserv, go to:
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>
> Hi all,
>
> I was just wondering if there is a simple method using basic imaging tools
> available with most research microscopes (DIC, phase contrast, confocal,
> etc.) to quantitatively determine the index of refraction of of the
> aqueous media in your imaging chamber or even in the cell interior.
>
> I know that the index of refraction inside the cell is not uniform, and I
> believe that several modes of imaging actually depend on this fact, but
> again, is there a way to quantitate this (and possibly map it in 2D by
> imaging)? I remember I had seen some papers a few years ago about
> quantitative phase contrast microscopy, but this is likely something very
> complicated with non-traditional optics (ie: not something you'd find in a
> basic microscope). I just need something quick and easy to get a handle on
> these numbers in real samples and to see how much they vary from sample to
> sample. How much variation in the index of refraction would one expect to
> find in cells, and is this cell type and/or environment dependent? Are
> there any table of values out there in the literature?
>
> And for reference, can someone point me to a good source of the numbers
> that usually get quoted for glass (coverslips), water, and cell interiors?
> I think these are typical values that are commonly used, but I don't know
> where they come from and how they were measured:
>
> glass (used in coverslips): ~1.523
> water ~1.3326
> inside cells ~ 1.38
>
> Thanks!
>
> John Oreopoulos
--
P. Johannes Helm, M.Sc. PhD
Seniorengineer
CMBN
University of Oslo
Institute of Basic Medical Science
Department of Anatomy
Postboks 1105 - Blindern
NO-0317 Oslo
Voice: +47 228 51159
Fax: +47 228 51499
WWW: folk.uio.no/jhelm
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