The Open Inorganic Chemistry Journal

2009, 3 : 26-32
Published online 2009 April 10. DOI: 10.2174/1874098700903010026
Publisher ID: TOICJ-3-26

Determination of Protonation Constants and Stability Constants of Lanthanides with Derivative of HDOTA Complexes by the UV-VIS Spectrophotometry and Potentiometry

Marie Reková and Vĕra Jedináková-Křížová
Department of Analytical Chemistry, Institute of Chemical Technology, Technicka 5, 166-28 Prague 6, Czech Republic;

ABSTRACT

Methods of static potentiometry and UV-VIS spectrophotometry were applied for the determination of protonation constants of (10-[4-aminobenzyl(hydroxyl)phosphonylmethyl]-1,4,7,10-tetraazacyclo-1,4,7-triacetic acid) (DOTA(NH2)) and stability constants of holmium and yttrium complexes with DOTA(NH2). The DOTA(NH2) protonation constants of [HA] (log β1 = 12.7); [H2A] (log β2 = 21.4) and [H3A] (log β3 = 27.9) were experimentally determined by the static potentiometry. The stability constants of Ho-DOTA(NH2) (log KHo DOTA(NH2) = 18.0) and Y-DOTA(NH2) (log KY-DOTA(NH2) = 17.8) complexes were determined by UV-VIS spectrophotometry using the competitive reaction of the DOTA(NH2) – metal complexes with Arsenazo III.

Keywords:

Lanthanide complexes, protonation, Cell labeling, stability constants, UV-VIS spectrophotometry, Arsenazo III, phosphonylmethyl]-1,4,7,10-tetraazacyclo-1,4,7-triacetic acid.