Fiske and Subbarow reagent . . .

[Dr. Timothy Strabala]

Greetings, All

I'm after formulation of the Fiske and Subbarow reagent, used for the
determination of inorganic phosphorus.

Sigma have Fiske and Subbarow reagent as a formulation of
1-amino-2-naphthol-4-sulfonic acid, and sodium sulfite and bisulfite.

I have the 1-amino-2-naphthol-4-sulfonic acid as a dry reagent from BDH. 
Some literature states that what I have is the functional reagent, whereas
others state that the aforementioned formulation with sodium sulfite and
bisulfite is the functional reagent.  If the latter is correct, what
solvent should I dissolve it in, and to what concentration?

Any help is appreciated.

Lana Perko 
<lana.perko at genesis.co,nz>