Gum Sandarac Mountants

Gum Sandarac has been used as a mounting medium suitable for material that cannot be cleared with xylene and must be coverslipped from ethanol. Euparal and its green cousin, Euparal Vert, are commercial mounting media that have enjoyed a degree of popularity for this purpose, but their exact formulas have not been revealed as they are trade secrets.

Mohr and Wehrle gave a formula which appears to provide much the same characteristics. It includes gum Sandarac dissolved in camsal (a mixture of phenyl salycilate and camphor) and includes a terpene, eucalyptol, with dioxane and paraldehyde. A formula published earlier by Shephard does not include dioxane, but is otherwise very similar. Either formula may have a small amount of copper oleate added to the eucalyptol during compounding, in which case the mounting medium will be green and resemble Euparal Vert. Copper is an effective mordant for hematoxylin and preserves the staining of nuclei with that dye.

Camsal
Camphor
Phenyl salicylate
One volume
One volume
Sandarac mountant (Shepherd)
Camsal
Gum Sandarac
Eucalyptol
Paraldehyde
10
30
20
10
mL
g
g
g
Sandarac mountant (Mohr and Wehrle)
Camsal
Gum Sandarac
Eucalyptol
Paraldehyde
Dioxane
10
40
20
10
20
mL
g
g
g
mL

If the gum Sandarac is dirty it should be dissolved in absolute ethanol to a suitable consistency, then filtered and dried by evaporation. This should be done under anhydrous conditions i.e. under a bell jar with anhydrous calcium chloride or silica gel.

 

Gray, Peter. (1954)
The Microtomist's Formulary and Guide. p. 638.
Originally published by:– The Blakiston Co.
Republished by:– Robert E. Krieger Publishing Co.
  Citing:–
    Shepherd, (1918)
    Transactions of the American Microscopical Society.
    Lancaster, Pennsylvania, USA.
  and:–
    Mohr and Wehrle, (1942)
    Stain Technology
    Geneva, New York, USA.


 

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