Determination Of Cadmium, Copper, Leadion Content In The Environment By Light Scattering Technique

Light scattering has been studied and used by a growing number of chemical workers for its simple operation, high sensitivity and rapid analysis from 1990s. At present, the technique is widely used in the field of chemical analysis, such as detection of heavy metal ions, biological macromolecules, surface active agents and pharmaceuticals. In this dissertation, the resonance light scattering intensity significantly enhanced, which were used to determination the content of cadmium (II) and copper (Ⅱ) in environmental water samples. In addition, we modified the light path from right angle scattering to the nearly 180°Backward light scattering on F-7000 fluorescence spectrophotometer. A nevol nearly 180°backward light scattering technique has been established for detection of lead(Ⅱ). The main contents are as follows:(1) In pH 6.8 Britton-Robinson(BR) buffer medium, a resonance light scattering (RLS) analytical method of cadmium (Ⅱ) was established based on the enhanced RLS signal due to the interaction of PFOS and chelate ion derived from the reaction between cadmium (Ⅱ) and phenanthorline (Phen). The enhanced RLS intensity at 307.0 nm is proportional to the content of cadmium (Ⅱ) in a range of 6.0-342.5 ng·mL-1. The limit of detection is 0.6 ng·mL-1. In this work, the optimum reaction conditions and the interference of foreign substances were investigated. This method has been successfully applied to determination of cadmium (Ⅱ) in tap water and laboratory waste water samples with RSD≤4.4%.(2) In pH 5.4 HAc-NaAc buffer medium, copper (Ⅱ) and Morin through the combination of complexation significantly enhanced resonance light scattering signals. The enhanced RLS intensity at 295.0 nm is proportional to the content of copper (Ⅱ) in a range of 0.08～12.0μmol/L. The limit of detection is 8.2 nmol/L. In this work, the optimum reaction conditions and the interference of foreign substances of the system were investigated. The absorption and fluorescence spectra of the system as well as the reaction mechanism were also discussed. This method has been successfully applied to the determination of copper (Ⅱ) in tap water and river water. The RSD is less than 4.5%.(3) A novel BLS method for the determination of lead (Ⅱ) has been developed base on the largely enhanced BLS signal at 399.0 nm due to the interaction of Ciprofloxacin (CIP), Congo red (CR) and lead ions by electrostatic forces and hydrophobic interactions to form ion-association complex in the pH 4.56 Britton-Robinson (BR) medium. The linear range of lead (Ⅱ) is 0.5～60.0μmol/L. The limit of detection (LOD) is 50 nmol/mL. In this work, the nearly 180°backward light scattering spectral, absorption and fluorescence have been studied, then discussed the system of reaction mechanism and using the backward light scattering investigated the appropriate reaction conditions, interference of foreign substances reaction mechanism. This method has been applied successfully for the determination of lead (Ⅱ) in environmental water samples and synthetic samples, the recovery between 91.0%～104.0%, RSD≤4.7%.