11-7-97

Dear all,

I want to cut a sample which contains water solvable matter. Normally after

cutting with a diamond knife the sections are swimming on a water surface.

Sothe water solvable part of the sample would be dissolved. Are there other

fluids available which can be used instead of water. I would appreciate any

answers and comments, especially if you have other ideas to solve the problem.

Kind Regards Rainer

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Rainer Ziel, Akzo Nobel Central Research, 63784 Obernburg, Germany

Rainer.Ziel@Akzo.NL

Dear Rainer,

A wide variety of fluids have been used for ultramicrotomy. Alcohols are

commonly used in cryoultramicrotomy of polymers. Some folks use a blend of

acetone and water to assist "spreading" of sections. References to DMSO and

ethylene glycol can be found in the literature.

The only caveats involved are the reactions of these fluids with the sample

(hence your question) and the reactions of these fluids with the materials

used to make your diamond knife. After you've decided what fluid you would

like to use, check with your diamond knife manufacturer regarding

compatibility.

Regards,

Joe Tabeling

Delaware Diamond Knives, Inc.

DDKJoe@aol.com

Many of the materials that we examined in the microscope at Polaroid

were both water soluble or swellable and also sensitive to organic

solvents. Consequently much of the sectioning was done dry - both for

light microscopy and electron microscopy. For ultramicrotomy, an

eyelash attached to an orangewood stick was used to pick up the section

and transfer it to a grid. The section, with a little manipulation,

made good contact with the carbon coat, and was usually stable in the

beam. Sometimes folding grids were used to help secure the sections.

****************************

Mary McCann

McCann Imaging

617-484-7865

617-484-2490 Fax

mccanns@tiac.net