DIN EN 15950:2010-12

This document specifies a method for the determination of N-(1,2-dicarboxyethyl)-D,L-aspartic acid (Iminodisuccinic acid, IDHA) in fertilizers. IDHA is measured and detected by HPLC-method after total conversion of the chelating agent into its iron- (III)-salt by adding an excess of a solution of iron-(III)-nitrate. In the HPLC-diagram IDHA is represented by two dominant peaks, the first one representing the R, S-Isomer (50 %), and the second one representing the R,R- as well as the R-Isomer (50 %). The precision of the method has been determined in an inter-laboratory trial with eleven laboratories participating and carried out on nine samples of fertilizer.