Collect. Czech. Chem. Commun.
1982, 47, 1086-1099
https://doi.org/10.1135/cccc19821086
Spectrophotometric study of the complex equilibria of cadmium(II) ions with 4-(2-pyridylazo)resorcine (PAR) using the SQUAD-G program and the method of determining Cd(II) ions with PAR
Sylva Vlčková, Luděk Jančář, Vlastimil Kubáň and Josef Havel
Department of Analytical Chemistry, J. E. Purkyně University, 611 37 Brno
Abstract
The existence of the red-orange CdLH+ complex (λmax = 406 nm, εmax = 1.78.104 mmol-1.cm2, log *β111 = -1.66+0.04) and CdL complex (λmax = 495 nm, εmax = 3.2.104 mmol-1. cm2, log *β112 = -8.25+0.05) was demonstrated in aqueous solutions of PAR with a concentration excess of Cd(II) ions. It was shown that a 10% v/v acetone medium containing Cd(II) in a concentration excess of PAR contains the following complexes: CdL2H2 (λmax = 507 nm, εmax = 1.4 . 104 mmol-1 cm(2), log*β122 = -2.85+0.04), CdL2H- (λmax = 495 nm, εmax = 6.25 . 104 mmol-1 cm2, log *β123 = -9.58 + 0.04) and CdL2-2 (λmax = 495 nm, εmax = 9.16 . 104 mmol-1 cm2, log *β124 = -17.33 + 0.06). The basic parameters of the individual complexes were determined by graphical interpretation using slope-intercept transformations and by numerical interpretation using the generalized SQUAD-G program. The statistical parameters of the spectrophotometric method of determining cadmium ions were evaluated from the linear part of the calibration curve using the STAT program.
