Characterization and analytical application of the ion-association complex crystal violet-cadmium bromopyrogallol red.
In the presence of polyvinylalcohol (PVA-124) and polyethylene glycol monooctylphenyl ether (emulsifier OP), cadmium ions(II) can form a colour ion-association complex with both Bromopyrogallol Red (BPR) and Crystal Violet (CV). In the NH(3)NH(4)Cl medium, the ion-association complex has a composition of Cd:BPR:CV = 1:1:2, and its corresponding molecular formula is [CV](2)[Cd(BPR)]. The maximum absorption of the colour complex is located at 654 nm with an apparent molar absorptivity of 1.79 x 10(5) l.mole(-1).cm(-1). Beer's law is obeyed for cadmium over the range 0-10 mug/25 ml. A highly sensitive spectrophotometric method for trace cadmium in water and zinc was developed with good precision and accuracy. The mechanism of the reaction is also discussed.
Zhao
Z Q
ZQ
Department of Chemistry, Hebei Normal University, Shijiazhuang city, Hebei Province, People's Republic of China.
Gao
R M
RM
Zhao
L C
LC