title: Characterization and analytical application of the ion-association complex crystal violet-cadmium bromopyrogallol red.
abstract: 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.
authors.affiliation: Department of Chemistry, Hebei Normal University, Shijiazhuang city, Hebei Province, People's Republic of China.
authors.forename: Z Q
authors.initials: ZQ
authors.lastname: Zhao
authors.forename: R M
authors.initials: RM
authors.lastname: Gao
authors.forename: L C
authors.initials: LC
authors.lastname: Zhao