SENSITIZATION OF STIBINE GENERATION - ANTIMONY DETERMINATION IN ENVIRONMENTAL-SAMPLES BY ATOMIC FLUORESCENCE SPECTROMETRY

This paper reports an improvement in the efficiency and selectivity of stibine generation and therefore an improvement in the analytical cha racteristics for antimony determination in environmental matrices by a tomic fluorescence. The sensitized method is achieved by generating th e stibine at 70 degrees C and using additional hydrogen flow to sustai n the atomization flame, which makes it possible to reduce the acid an d borohydride concentration and therefore to economize the process and reduce the inherent pollution risks due to the high concentrations us ed. Furthermore, a new phase separator in which temperature is control led and dead time significantly reduced has been designed and incorpor ated in the hydride generation system. Selectivity is increased by wor king in an organized medium, Triton X-100 being the surfactant chosen as the most appropriate. Under the optimized conditions, a limit of de tection of 0.3 mu g l(-1) of Sb was achieved, with a precision of 1.4% for 8 mu g l(-1), and the calibration graph was linear from 0.3 to 2. 7 x 10(3) mu g l(-1). The sensitized method performed satisfactorily w hen evaluated by the determination of Sb in standard reference materia l (SRM 1648) of atmospheric urban particulate matter and by recovery s tudies in sea-water, tap water and in air samples collected on silica filters. The recovery in the enriched samples was 99 +/- 1% in all cas es. The proposed method was successfully applied to the determination of Sb in samples of Bilbao urban air, being 13.2 +/- 0.3 ng m(-3), the antimony concentration found.