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Formalin Picric Trichloroacetic (FPT)

Formalin Picric Trichloroacetic (FPT)

Formula

MaterialAmount
Strong formalin150mL
Picric acid, sat in ethanol185mL
Ethanol, 100%235mL
Water430mL
Trichloroacetic acid5g

Dissolve the trichloroacetic acid in the water, then combine with the other ingredients.

Description

Davenport says this solution gives results very similar to Bouin’s fluid, but with less tendency to swell connective tissue. In addition, the ethanol content facilitates penetration of fatty tissues, including brain and spinal cord. PFT stands for picric-formalin-trichloroacetic.

The method he gives specifies 850 mL of a 2% picric acid solution in 50% ethanol, plus the formalin and trichloroacetic acid. The amounts of saturated alcoholic picric acid, ethanol and water given above provide that, based on picric acid saturating in ethanol at 9%.

Average sized pieces of tissue should be fixed following overnight treatment. No particular aftertreatment was given.

Safety Note

Prior to handling any chemical, consult the Safety Data Sheet (SDS) for proper handling and safety precautions.

References

  1. Davenport, H.A., (1960),
    Histological and histochemical techniques,
    W. B. Saunders Co., London, UK., Oxford, UK.