This document specifies the method for the determination of free, chelated or complexed micronutrients and chelating and/or complexing agents present in compound inorganic micronutrient fertilizers.
This method applies to compound inorganic micronutrient fertilizers when micronutrients are chelated and/or complexed.
The method is based on the determination of the following specific parameters :
- the water-soluble micronutrient concentration;
- the fraction of chelated micronutrients in relation;
- identification of chelating agents EDTA, DTPA, HEEDTA, IDHA, [S,S]–EDDS, [o,o] EDDHA, [o,o] EDDHMA, [o,p] EDDHA, HBED and EDDHSA;
- the fraction of complexed micronutrients;
- identification of complexing agents (lignosulfonates, heptagluconic acid (HGA)).
The method is based on
- ICP (inductive coupled plasma) or FAAS (flame atomic absorption spectrometry) measurement of the concentration of water-soluble micronutrients according to EN 16963 or EN 16965 after extraction according to EN 16962;
- LC (liquid chromatography) measurement of the chelating agents according to EN 15950, EN 13368-1, EN 13368-2, EN 13368-3, EN 15451, EN 15452;
and/or complexing agents according to EN 16109 and EN 16847;
- determination of the concentration of chelated micronutrients by CEN/TS 17786-1 and/or CEN/TS 17786-2;
- determination of the complexed micronutrients by EN 15962.
To avoid duplication of the analytical methods, CEN/TS 17786-2 describes the determination of micronutrients and the identification and determination of chelating agents.