抄録
A combined method of electrothermal vaporization and ICP-MS was studied for microtrace analysis. A 5μl volume of a sample was placed on a tungsten filament(0.2mm in diam.×45mm) and desolvated electrothermally. Arsenic in the residue was then vaporized by increasing the temperature of the filament to 2450°C with the aid of a capacitor(0.22F) and then carried in an argon stream to an ICP torch. The filament was used repeatedly at least 100 times. The relative standard deviation(n=10) for signal intensities of 15pg As was ca. 10%, with an absolute detection limit(3σ) of 1pg. The proposed method was applied to the determination of arsenic in a certified reference human hair sample. The analytical results obtained for the sample(decomposed with 14M nitric acid and hydrogen peroxide) were 0.35±0.03μg g-1, which almost coincided with the certified values(0.31±0.02μg g-1).
