Abstract
Trace amount of vanadium in river water was determined by the graphite furnace atomic absorption spectrometry using pyrolytic graphite coated tube after three coprecipitation treatments. Ferric hydroxide, hydrous titanium oxide, and the mixture of them were used as coprecipitation reagents. The recoveries of vanadium were nearly 100 % when used ferric hydroxide and hydrous titanium oxide at pH 6 to 9, and 4 to 8, respectively. Their C. V. % were 3.5 % and 3.4 % respectively. When used the mixed reagent of ferric hydroxide and hydrous titanium oxide, the recovery and C. V. % of vanadium were almost 100 % and 1.7 % at pH 4 to 8, respectively. Moreover, the total amount of reagent was reduced, and the precision of analysis was improved. The precipitate was collected by filtration with 0.45 μm millipore filter, and was digested with nitric acidhydrogen peroxide to reduce background absorption due to coprecipitated organic materials. To correct the background absorption due to coprecipitated inorganic salts, higher-brilliant thermal cathode type deuterium lamp was used. The sensitivity of this graphite furnace atomic absorption measurement using pyrolytic graphite coated tube was 10 to 20 fold than that of the measurements using uncoated tube or tantalum or tungsten carbide coated tube. Samples of Watarase river basin were determined for the investigation of water pollution by vanadium, and the satisfactory results were obtained.
