This Ethiopian Standard specifies a spectrophotometric molybdovanadophosphate method for the determination of available phosphorous content (expressed as diphosphorous pentaoxide) of fertilizers.
The method is not applicable to materials yielding coloured solutions or solutions containing ions other than orthophosphate which form coloured complexes with molybdovanadate. It is not recommended for basic slag.
NOTE - Attention is drawn to ES ISO 6598, which specifies a Gravimetric method using quinine phospho molybdate for the determination of phosphorous content of fertilizers (Reference method).
ES 399-2000 history
2000ES 399-2000 Determination of available phosphorus content of fertilizers Spectrophotometric method Molybdenum vanadium phosphate method