Chromatographic separation of metals using DOTA-based chelators

A method of chromatographic separation of rare earth elements, actinides and/or s-, p- and d-block metals, from a mixture of at least two metal ions, the method comprising:

• (a) providing a mixture of at least two different metal ions chosen from rare earth metal ions, actinide ions and/or s-, p- and d-block metal ions,
• (b) forming chelates by contacting metal ions comprised in the mixture with at least one compound of general formula (I):
• A is N or C substituted with one of H, halogen (Cl, Br, F), SO3H, C1-4 alkyl, aryl, hetaryl, C—O—C1-16 alkylamino,
• Z and Z1 independently are N or C substituted with one of H, halogen (Cl, Br, F), SO3H, C1-4 alkyl, aryl, hetaryl, C—O—C1-16 alkylamino,
• E=O, S or P;
• R1 is independently substituted or unsubstituted C4-15alkylaryl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle, or substituted or unsubstituted heteroaryl, wherein the substitution is by one or more moiety(ies) selected from a group consisting of imide, —C(O)(CH2)0-3CH3, C2-5carboxyl, —(CH2)1-3C(O)(CH2)0-3CH3, nitro, amino, thiol, succinimide, maleimide, aminooxyl, acetylene, N3, acetamino, azide, —C(O)O(CH2)1-3CH3, —OC(O)(CH2)0-3CH3, halogen, C1-5alkynyl, and NCS;
• and a=0-5;
• (c) subjecting the chelates to chromatographic separation, wherein optionally at least one separated metal chelate can be subjected to at least one further chromatographic separation in order to increase the purity of the at least one separated metal chelate;
• and, optionally,
• (d) obtaining the metal from the at least one separated metal chelate.