| || || Chand, Vimlesh.|
| || || Application of kinetic catalytic spectrophotometric method for the speciation of selenium in environmental water |
Institution: University of the South Pacific.
Call No.: Pac QD 181 .S5 C43 2007
Copyright:Under 10% of this thesis may be copied without the authors written permission
Abstract: A simple and sensitive catalytic kinetic spectrophotometric method was optimised, validated and successfully applied for the determination of inorganic selenium at parts per billion levels in synthetic and real water samples. Experimental variables affecting thesensitivity of method were investigated and optimum conditions were established. Twotechniques of data treatment, Initial rate and Fixed time method, were used and comparedfor their sensitivity. The limit of detection of the methods were found to be 1.3 μg L-1 and14.7 μg L-1 for the Initial rate and Fixed time method, respectively. Standard reference materials consisting of selenium standards and real water sample were used to validate the method. The accuracy and precision was determined using recovery studies in the lower range of selenium concentration. The reproducibility of the method was investigated using quality control procedures. Different sample digestion techniques were studied for determining the concentrations of different inorganic selenium species in water. The existing standard digestion techniques, HCl method for the determination Se(IV) and American Public Health Association method for the determination of total Se were found to be suitable with minor modifications. Within and between day analysis of selenium standards showed very good reproducibility and precision of the method. The proposed method was applied to environmental water samples collected from Suva and Labasa areas in Fiji. Overall, it was found that the proposed method is reliable and accurate for environmental monitoring of inorganic Se in the aquatic system. In addition, water samples tested showed that Se levels were below detection limit of the method, hence within the limits set by the World Health Organisation.