Nature of impurities in fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+) chelates.

Abstract

Iron chelates derived from ethylenediaminedi(o-hydroxyphenylacetic) acid (EDDHA), ethylenediaminedi(o-hydroxy-p-methylphenylacetic) acid (EDDHMA), ethylenediaminedi(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA), and ethylenediaminedi(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA) are remarkably efficient in correcting iron chlorosis in plants growing in alkaline soils. This work reports the determination of impurities in commercial samples of fertilizers containing EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+). The active components (EDDHMA/Fe(3+), EDDHSA/Fe(3+), and EDDCHA/Fe(3+)) were separated easily from other compounds present in the fertilizers by HPLC. Comparison of the retention times and the UV-visible spectra of the peaks obtained from commercial EDDHSA/Fe(3+) and EDDCHA/Fe(3+) samples with those of standard solutions showed that unreacted starting materials (p-hydroxybenzenesulfonic acid and p-hydroxybenzoic acid, respectively) were always present in the commercial products. 1D and 2D NMR experiments showed that commercial fertilizers based on EDDHMA/Fe(3+) contained impurities having structures tentatively assigned to iron chelates of two isomers of EDDHMA. These findings suggest that current production processes of iron chelates used in agriculture need to be improved.

• Authors: Ana Alvarez-Fernández, Mauro A Cremonini, Miguel A Sierra, Giuseppe Placucci, Juan J Lucena
• Journal: Journal of agricultural and food chemistry (J Agric Food Chem) Vol. 50 Issue 2 Pg. 284-90 (Jan 16 2002) ISSN: 0021-8561 [Print] United States
• PMID: 11782196 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ethylenediamines
• Fertilizers
• Iron Chelating Agents
• ethylenediaminedi-(o-hydroxy-p-methylphenylacetic)acid
• ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid)

Topics

• Chromatography, High Pressure Liquid
• Ethylenediamines
• Fertilizers (analysis)
• Iron Chelating Agents (analysis)
• Isomerism
• Magnetic Resonance Spectroscopy