Abstract (EN):
The complexation behavior of four systems involving cadmium(II) or zinc(II) in aqueous solutions with the biological buffers 3-[N,N-bis(2-hydroxyethyl)amino]-2-hydroxypropanesulfonic acid (DIPSO), and [(2-hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]-1-propanesulfonic acid (TAPS) was studied by direct current polarography (DCP) and glass electrode potentiometry (GEP), at 25.0 +/- A 0.1 A degrees C and ionic strength 0.1 mol center dot dm(-3) KNO3. Except for the Cd-TAPS system, for which full characterization of the system was possible either by DCP or GEP, full characterization of the other metal-buffer systems (Zn-DIPSO, Zn-TAPS and Cd-DIPSO) was only possible using DCP. For Zn-buffers systems, ZnL+ and (where L stands for buffer) were identified. For the Zn-DIPSO system, the overall stability constant values (as log(10) beta) are 2.1 +/- A 0.2 and 13.4 +/- A 0.2, respectively. For the Zn-TAPS system, the overall stability constants values (as log(10) beta) are 2.4 +/- A 0.1 and 12.9 +/- A 0.3, respectively. For the Cd-DIPSO system, the overall stability constants values (as log(10) beta) of CdL+ and CdL(OH) are 2.9 +/- A 0.1 and 6.9 +/- A 0.3, respectively. For the Cd-TAPS system, only the species CdL+ was identified with log(10) beta = 2.5 +/- A 0.1.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
18