Bensley's PTAB

Phosphotungstic Acid Brazilin


Brazilin 0.05 g Dissolve the brazilin in a little of the water.
Phosphotungstic acid 1 g Dissolve the phosphotungstic acid in the remaining water.
Distilled water 100 mL Combine the solutions.
Solution B
Phosphomolybdic acid 1 g
Water blue 0.2 g
Distilled water 100 mL

Tissue sample
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are likely to be satisfactory.


  1. Bring sections to water via xylene and ethanol.
  2. Place in PTAB for 1-several hours.
  3. Wash with water.
  4. Place into solution B for 1-5 minutes
  5. Rinse quickly with distilled water.
  6. Dehydrate with ethanols.
  7. Clear with xylene and mount with a resinous medium.

Expected results


  1. Two drops of hydrogen peroxide may be added to the PTAB solution to ripen.
  2. The PTAB solution lasts about three days.
  3. Bensley comments that sections may be pretreated with a solution of ammonium stannic chloride (concentration not given) for a brief period, but doing so will increase contrast at the expense of staining delicacy.


Bensley R. R. and Bensley, S. H., (1938)
Handbook of Histological and Cytological Technique.
U. Chicago Press, Chicago, USA




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