Acetylation

This procedure is used in the PAS reaction to block hydroxyl and amino groups. It does this by forming esters with them. As a consequence some carbohydrates fail to react with the Schiff's reagent. This may be used as a means of identifying them, particularly if done in conjunction with other blocking procedures.

Solution

Chemical	Amount
Acetic anhydride	16 mL
Pyridine, anhydrous	24 mL

 

Procedure
Place dewaxed sections into the solution at the temperature specified for the time given.

Tissue	Temp	Time	State
Cartilage	58°C	6 hours	complete
Cartilage	25°C	24 hours	complete
Glycogen	25°C	6 hours	Almost complete
Epithelial mucin	25°C	6 hours	complete

 

Reference

Lillie, R.D., (1954)
Histopathologic technique and practical histochemistry Ed.2
Blakiston, New York, USA.