Typically, the bifunctional ligand is first conjugated to a protein, peptide, or an antibody prior to complexation. The key to successful complexation is to make sure the conjugate is adequately buffered at a slightly acidic pH prior to introduction of the lanthanide. If the metal experiences a basic pH upon addition, it is likely to form the hydroxide species [Ln(OH)3] which undergoes complexation at a much slower rate relative to the LnCl3 species. Formation of the hydroxide can be detected visually by the appearance of a slightly turbid suspension. Ultimately this condition leads to a reduce percentage of complexation.

Isothiocyanate bifunctional ligands react quickly with primary amines at neutral to moderately basic conditions whereas the NHS-ester begins to react under slightly acidic conditions. Both will undergo competitive hydrolysis under these same conditions which reduces conjugation efficiency. For this reason it is important to combine the bifunctional ligand with the targeting vector in a properly buffered medium and to avoid preparing the bifunctional ligand solution too far in advance. It is also advantageous to use an excess of bifunctional ligand as some degree of hydrolysis is unavoidable.

Our products are classified as organic non-hazardous chelating agents for basic research. International shipments are assigned HS code 2933.99