This document specifies a method for the determination of the chelated fraction of micronutrients for fertilizers containing one or many micronutrients chelated by EDTA, DTPA, HEEDTA, IDHA or [S,S]-EDDS in fertilizers.
This method is used for inorganic micronutrient fertilizers when micronutrients are chelated only by EDTA, DTPA, HEEDTA, IDHA or [S,S]-EDDS or for mixtures in which EDTA, DTPA, HEEDTA, IDHA or [S,S]-EDDS is one of the chelating agents.
The method is applicable to all inorganic micronutrient fertilizers containing EDTA, DTPA, HEEDTA, IDHA or [S,S]-EDDS as chelating agent for contents > 0,1 % (w/w).
The method is based on ICP or AAS measurement of the concentration of micronutrients according to EN 16963 or EN 16965 after water extraction according to EN 16962 and LC measurement of the chelating agents according to EN 15950, EN 13368-1 and EN 13368-3.