Novel preconcentration techniques for the determination of trace metal ions in environmental matrices

The analysis of single or multiple metal ions in trace amounts in environmental matrices is a general problem. As a result methods for the selective preconcentration of trace metals are continually investigated. Successful development and application of four novel preconcentration techniques for the determination of trace metal ions are described in the bulk of this thesis. In chapter 1 traditional and novel preconcentration approaches including their inherent advantages and disadvantages are described. column switching RPHPLC technique coupled with UV/VIS detection for trace level determination of Cu(II), Fe(III) and Al(III) in waste water and beer samples is described in chapter 2. Metal precomplexation with 8-hydroxyquinoline enabled spectrophotometric detection at 400 nm. Limits of detection of 5 ppb for Al(III) and 40 ppb for Cu(II) and Fe(III) were obtained. The use of ligand coated stationary phases incorporating a novel CTAB/DTC ion pair for copper determination in mine waste water is described in chapter 3. The CTAB-DTC precolumn has been used for on-site sample loading. Direct incorporation of the loaded precolumn back into the switching system decreased overall sample analysis time considerably. Precolumn preparation was extremely reproducible with < 3 % variation for a batch size of 50. Preconcentration of Cu(II) using microbial biomass is described in chapter 4. Off-line copper determination using FAAS and on-line determination using HPLC coupled to a UV/VIS spectrophotometer was possible using this novel stationary phase. Rhizopus arrhizus (unlyophilized) packing material, particle size 90 % recovery was achieved. Surfactant enhanced adsorptive stripping voltammetry for trace level determination of aluminium in water and soil samples is reported in chapter 5. This electroanalytical preconcentration method allowed the determination of aluminium as its Solochrome Violet RS (SVRS) complex in the presence of a cationic surfactant, CTAB