Evaluation of electrochemical hydride generation for the determination of total antimony in natural waters by electrothermal atomic absorption spectrometry with in situ concentration

A continuous-bow (timed injection) electrochemical hydride generation system was developed for the determination of total Sb in river water and sea-water. Lead was used as cathode material. for the production of stibine. Both Sb-III and Sb-V were equally converted into their hydrides by electrochemical means with 92+/-4% efficiency. The hydride was trapped in a Pd-coated graphite furnace prior to atomization. An absolute detection limit of 45 pg (3s(blank)) and a concentration detection limit of 0.02 mu g l(-1) were obtained using 2 mi sample volumes. The precision of replicate measurements at the 0.2 pg l(-1) level (0.5 ng absolute mass level) was better than 6% relative standard deviation. The accuracy of the approach was verified through the analysis of National Research Council of Canada certified reference materials SLRS-2 and SLRS-3 River Water and NASS-4 Open Ocean Sea-water.