The procedure is applicable to phosphorus-containing fertilisers such as the superphosphates, mixed fertilizers, nitrophos and ammophos complexes and fertilizer row materials. The spectrophotometric finishing alternative is not applicable to materials yielding colored water extracts or water extracts containing ionc other than orthophosphato whiob forn colored com-plexes with molybdovanadate, and is not recommended for basic slag. The volumetric finishing alternative may be used in all cases.
PTS 123-1970 history
1970PTS 123-1970 Standardization of the Method of Test for the Determination of Water-soluble Phosphorus Content of Fertilizers