Fluorimetric determination of selenium in cast iron with naphthalene-2,3-diamine
By using naphthalene-2,3-diamine a simple and rapid fluorimetric method for the determination of selenium in cast iron has been developed. No separations from interfering elements are necessary, the interference caused by iron(III) being overcome by its reduction to iron(II) with hydroxylammonium chloride and that of other elements found in cast iron by the addition of ethylenediaminetetra-acetic acid. Suitable conditions for the formation and extraction of the fluorescent naphtho[2,3-d]-2,1,3-selenadiazole (4,5-benzpiazselenol) have been found. The method covers the range 0·01 to 0·10 per cent. of selenium, but with suitable modifications higher and lower contents can be determined. At the 0·10 per cent. level the standard deviation is 0·003 per cent.