Increased shelf-life and feulgen staining intensity of a modified trichloracetic acid-Schiff reagent.

Two modified formulae for the preparation of trichloracetic acid (TCA)-Schiff reagent have been presented in this communication. The modifications involve addition of 250 mg or 500 mg of trichloracetic acid per 100 ml of a 0.5% aqueous solution of basic fuchsin in place of NTCA which means 1.63 g of TCA per 10 ml of distilled water to be added to 100 ml of the dye solution. The use of TCA-Schiff reagents prepared by the modified method reveals a considerably faster Feulgen staining, a more intense colouration of the nuclei and a longer shelf-life of the dye-SO2 reagents as compared with the standard TCA-Schiff of Bloch and Godman. Possible interpretations for these phenomena have been presented.