BS EN 13368-2 is a standard that serves technical specifications for determining Fe chelated by EDDHA, EDDHMA and HBED in fertilizers, enabling the supplementation of iron deficiency at all pH values.
BS EN 13368-2 specifies a method for the chromatographic determination of the iron chelated by each individual ortho(hydroxy)-ortho(hydroxy) isomer of the chelating agents EDDHA, EDDHMA and by HBED in fertilizers containing one or more of these substances.
BS EN 13368-2 method allows the identification and the determination of the total concentration of water-soluble iron chelates of these chelating agents. Also, after derivatisation with Fe, the soluble amount of the chelating agents can be determined when other micro-nutrients, besides Fe, are present in fertilizers containing [o,o] EDDHA, [o,o] EDDHMA or HBED.
BS EN 13368-2 method applies to EC fertilizers covered by Regulation (EC) No 2003/2003 [4]. It applies to a mass fraction of the metal chelate of at least 0.625 %.
Note 1: EDDHA and EDDMHA exist in several different isomeric forms. Positional isomers for hydroxy or methyl groups as well as stereoisomers are known. Both meso and dl-racemic forms of EDDHA and EDDMHA are allowed by regulation. Para, meta and ortho methyl positional isomers of EDDHMA are grouped in BS EN 13368-2 method.
Note 2: At present, analytically pure standards only exist for EDDHA, EDDHMA and HBED. All other substances being unavailable as a standard, the influence of their eventual presence in the samples has not been studied.
Note 3: The meso and the dl-racemic forms of EDDHA and EDDHMA can be determined separately by BS EN 13368-2 method.
BS EN 13368-2 on determining Fe chelated by EDDHA, EDDHMA and HBED in fertilizers applies to:
A chelating agent is a chemical molecule that combines with metal ions to generate stable water-soluble metal complexes. Chelating agents keep metals soluble in the soil and allow them to be taken up by plants. Although the two components are separated in the roots, they can be transferred to the leaves.
BS EN 13368-2 provides users guidance on principle, interferences, reagents, apparatus, sampling, procedure, expression of results, precision and test report to enhance the chemical stability of fertilizers and increase plant uptake of micronutrients such as Fe.
BS EN 13368-2 provides users guidance on the ion pair chromatography method to determine chelating agents in fertilizers. BS EN 13368-2 also provides users with a step-by-step procedure for the technique enabling users to do the process correctly.
The adoption of BS EN 13368-2 allows users to determine Fe chelated by EDDHA, EDDMHA and HBED, enhancing the bioavailability of Fe micronutrient to improve crop yields.
BS EN 13368-2:2017 supersedes BS EN 13368‑2:2012, which is now withdrawn. Changes in BS EN 13368-2:2017 include -
EN 13368-2:2017