The terms Pseudo-Schiff and Pseudo-PAS refer to the use of dyes other than pararosanilin or basic fuchsin to make a Schiff type solution and use it for demonstrating carbohydrates. While an interesting exercise, it has little practical use except for the occasional demonstration of fungi with a fluorescent pseudo-Schiff solution made with acriflavine. The following dyes, among others, have been suggested.
|Dye||CI Number||Colour||Dye||CI Number||Colour|
|Azure A||52005||blue||Azure C||52005||blue|
|Crystal violet||42555||blue-violet||Methyl violet||42535||violet|
|Methylene blue||52015||blue||Safranin O||50240||red|
1% hydrochloric acid in 70% ethanol
A suitable counterstain
Prepare a solution according to the instructions for acriflavine Schiff reagent, or another formula, if preferred. Note that they will likely not become colourless, so leave for 48 hours, then filter the solution and store refrigerated.
5µ paraffin sections of neutral buffered formalin fixed tissue are suitable. Other fixatives are usually satisfactory, although glutaraldehyde should be avoided.
Culling C.F.A., (1963)
Handbook of histopathological and histochemical techniques Ed. 2
Butterworth, London, UK.