method for the isolation and determination of ferric ethylenediamine di(o-hydroxyphenylacetic acid) in soil studies

• Published in: Plant and soil Vol. 34; no. 1; pp. 241 - 247
• Main Authors: Elgala, A.M, Maier, R.H, Fuller, W.H
• Format: Journal Article
• Language: English
• Published: Martinus Nijhoff 01-02-1971
• Subjects: Acid soils; Chelates; Clay loam soils; Clay soils; fertilizers; Iron; SHORT COMMUNICATION; Soil biochemistry; Soil organic matter; Soil science; Soil solution; Soil treatment
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/BF01372780

Contraversal results about the behaviour of Fe-EDDHA in soils is thought to be due to the indirect methods used for determining the iron chelate compound in soils. The purpose of this investigation is to develop a method for isolation of Fe-EDDHA from soil extracts inorder to be determined separatly. A 4% solution of tetra-n-heptylammonium iodide in ethyl alcohol was found effective in forming a water-insoluble but n-amyl alcohol-soluble compound of Fe-EDDHA. It was found that the absorption spectra of the iron chelate extracted with n-amyl alcohol has an absorption maximum of 480 mμ corresponding to that of iron chelate of the aqueous solution. The extracted iron chelate adhers to Beer's low in the range of 0 to 120 ppm of Fe-EDDHA. The method of Fe-EDDHA extraction was found to be selective for the isolation of the iron chelate from other soluble compounds. The procedure was also found to be highly efficient in quantitative isolation of Fe-EDDHA, with percent recovery ranging from 97-100. The incubation study of Fe-EDDHA in different soils indicated that the loss of Fe-EDDHA is associated with the organic matter content in the soil. The colorimetrie determination of the total metal chelates did not indicate any replacement of other metals for the chelated iron in the soil.