Synthesis of o,p-EDDHA and its detection as the main impurity in o,o-EDDHA commercial iron chelates.
Ethylenediamine-N,N'bis(o-hydroxyphenyl)acetic acid (o,o-EDDHA) is one of the most efficient iron chelates employed to relieve iron chlorosis in plants. However, the presence of positional isomers of EDDHA in commercial iron chelates has been recently demonstrated, and among them, it has been claimed that ethylenediamine-N(o-hydroxyphenylacetic)-N'(p-hydroxyphenylacetic) acid (o,p-EDDHA) is the main impurity present in EDDHA fertilizers. Here we report the preparation of o,p-EDDHA, a compound whose synthesis had not been previously reported. The synthetic o,p-EDDHA is able to form ferric complexes, and it has been used as a standard in the analysis of the impurities of commercial iron fertilizers. The presence of o,p-EDDHA/Fe(3+) in commercial samples has been unambiguously demonstrated by HPLC.
Gómez-Gallego
Mar
M
Departamento de Química Orgánica, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
Sierra
Miguel A
MA
Alcázar
Roberto
R
Ramírez
Pedro
P
Piñar
Carmen
C
Mancheño
María José
MJ
García-Marco
Sonia
S
Yunta
Felipe
F
Lucena
Juan José
JJ
D002851:Chromatography, High Pressure Liquid; D005029:Ethylenediamines / Q000032:analysis / Q000737:chemistry*; D005308:Fertilizers / Q000032:analysis*; D007502:Iron Chelating Agents / Q000032:analysis / Q000737:chemistry*; D007536:Isomerism
D005029:Ethylenediamines; D005308:Fertilizers; D007502:Iron Chelating Agents; C011813:ethylenediamine-N,N'-bis(2-hydroxyphenylacetic acid)