de Tomasi's
Schiff Reagent

Solution

Ingredient	Amount
Pararosanilin	1 g
Distilled water	200 mL
Potassium metabisulphite	1 g
Hydrochloric acid, 1N	20 mL
Activated charcoal (powder)	2 g

 

Preparation
Heat the distilled water to boiling in an oversized Erlenmeyer flask.
Take from the heat, and immediately add the dye.
Be careful, as it foams.
Shake well until the dye is dissolved.
Cool to 50°C then add the hydrochloric acid.
Shake well to dissolve.
Cool to 25°C, and add the metabisulphite.
Stopper well and store in the dark for one to two days.
If not water clear, add activated charcoal and shake for about a minute.
Filter the solution.
Store at 0-5°C in a tightly stoppered bottle.

 

Notes

1. This solution differs from Feulgen & Rossenbeck's Schiff reagent by specifying potassium metabisulphite as the source of sulphur dioxide instead of sodium bisulphite. However, according to the Merck Index, commercial sodium bisulphite is made predominantly of sodium metabisulphite, and for most purposes they are interchangeable.
2. The solution should be colourless or very pale amber. Brown solutions will often stain poorly. Usually these have been made from a batch of basic fuchsin containing too little pararosanilin.

 

Reference

Culling C.F.A., (1974)
Handbook of histopathological and histochemical techniques Ed. 3
Butterworth, London, UK.

Susan Budavari, Editor, (1996)
The Merck Index, Ed. 12
Merck & Co., Inc., Whitehouse Station, NJ, USA