Periodic acid solutions
The following formulae for periodic acid solutions in the PAS reaction are given by Lillie. He comments that it seems to make no difference which aqueous solution is used as a routine. It should be noted that the 90% ethanol variant takes a much longer time than the others. However, it is reputed to demonstrate all oxidisable material.
Common preference today is for a simple 0.5% or 1% aqueous solution, although a 0.1% solution is satisfactory. The solution is usually applied for about 10 minutes, even though some early recommendations were for 2-3 minutes. Within limits, the longer the periodic acid as applied the darker the staining for the same time in Schiff's reagent. Periodic acid solutions may be re-used.
In the chart below, the amount of oxidant given is intended to be dissolved in 100 millilitres of the solvent. All of the solutions are stable.
|McManus||Periodic acid||0.5 g||Distilled water||5 minutes|
|Lillie A||Sodium iodate||1 g||Nitric acid, 0.5% aqueous||10 minutes|
|Lillie B||Potassium iodate||0.8 g||Nitric acid, 0.3% aqueous||10 minutes|
|Lillie C||Potassium iodate||0.69 g||Nitric acid, 0.3% aqueous||10 minutes|
|Hotchkiss A||Periodic acid||0.8 g||Sodium acetate, 0.02M aqueous||5 minutes|
|Hotchkiss B||Periodic acid||0.8 g||Sodium acetate, 0.02M in 70 ethanol||5 minutes|
|Mowry||Periodic acid||1 g||90% ethanol||120 minutes|
Lillie, R.D., (1954)
Histopathologic technique and practical histochemistry Ed.2
Blakiston, New York, USA.