Determination of antimony by continuous hydride generation coupled with non-dispersive atomic fluorescence detection

Abstract

A sensitive method for the determination of Sb at ultratrace levels was developed by coupling continuous hydride generation with non-dispersive atomic fluorescence detection. A miniature argon–hydrogen diffusion flame was employed as the atomizer and a commercially available electrodeless discharge lamp as the light source. One of the main problems was the scattering signal generated by small droplets of solution which markedly deteriorated the signal-to-noise ratio. A simple way to remove the scattering signal was to operate under mild reaction conditions in order to minimize droplet formation. Under the optimized conditions, a limit of detection of 22 pg cm^–3 of Sb (3s of the blank) was achieved, with a precision of 1.2% at the 5 ng cm^–3 level and the calibration graphs were linear over more than 4 decades of concentration. L-Cysteine was employed both in the pre-reduction step and in the control of the interference effects arising from concomitant elements and acid mixtures. The analytical procedure was applied to the determination of Sb in certified reference materials of sediments, metallic copper and riverine water.