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PAS (Periodic Acid Schiff) Staining Protocol
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PAS (Periodic Acid Schiff) Staining Protocol

Description: This method is used for detection of glycogen in tissues such as liver, cardiac and skeletal muscle on formalin-fixed, paraffin-embedded tissue sections, and may be used for frozen sections as well. The glycogen, mucin, and fungi will be stained purple and the nuclei will be stained blue. 

Fixation: 10% formalin.

Section:Âparaffin sections at 5 um.

Solutions and Reagents:

0.5% Periodic Acid Solution:

      Periodic acid ---------------------- 0.5 g

      Distilled water -------------------- 100 ml

Schiff Reagent:

      Test for Schiff reagent: Pour 10 ml of 37% formalin into a watch glass. To this add a few drops of the Schiff reagent to be tested. A good Schiff reagent will rapidly turn a red-purple color. A deteriorating schiff reagent will give a delayed reaction and the color produced will be a deep blue-purple. 

Mayer’s Hematoxylin Solution:


1.    Deparaffinize and hydrate to water.

2.    Oxidize in 0.5% periodic acid solution for 5 minutes.

3.    Rinse in distilled water.

4.    Place in Schiff reagent for 15 minutes (Sections become light pink color during this step).

5.    Wash in lukewarm tap water for 5 minutes (Immediately sections turn dark pink color).

6.    Counterstain in Mayer's hematoxylin for 1 minute.

7.    Wash in tap water for 5 minutes.

8.    Dehydrate and coverslip using a synthetic mounting medium.


      Glycogen, mucin and some basement membranes --- red/purple

      Fungi ------------------------------------------------------ red/purple

      Background ----------------------------------------------- blue

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