Direct determination of nanogram amounts of iodine by atomic-absorption spectroscopy using a graphite-tube atomizer

The direct determination of iodine by AAS at its 183.0 and 178.2 nm resonance lines by using a small graphite-tube atomizer, electrodeless discharge-lamp source and vacuum monochromator is described. Optimum conditions for the determination of iodine have been established; similar sensitivity is obtained when iodide or iodate samples are examined. With 10 mul aqueous samples sensitivities (for 1% absorption) of 4 x 10(-10) g and 2 x 10(-10) g of I were obtained at 183.0 and 178.2 nm respectively; a detection limit of 2 x 10(-10) g was observed at both lines. Non-specific molecular absorption from common inorganic salts causes interference with the determination; the iodine non-resonance line at 184.4 nm may be employed to correct for this interference when moderate amounts of common salts are present.