Dissolved Fe is normally estimated by titration with standard pot.dichromate in presence of sulphuric acid. I like to get idea whether this could be done in alkaline medium.
We recommend to determine Fe II with Cerium(IV) sulfate solution and standardize the solution with Iron(II) ethylenediamine sulfate volumetric standard in an acid milieu (add sulfuric acid).
Also the Potassium permanganate solution is possible to us an standardize it with d- sodium oxalate.
According to literature (Jander Jahr) you also can use Potassium dichromate solution, but only in acidic milieu. The Potassium dichromate solution needs to be standardized with Sodium thiosulfate solution which is standardized with potassium iodate.
As far as I know in an alkaline solution we will get a precipitation!
From Bettina Straub-Jubb Global Product Manager Titration Merck KGaA