Analytical strategies for determination and environmental impact assessment of inorganic antimony species in natural waters using hydride generation atomic fluorescence spectrometry (HG AFS)

Abstract

This study proposes an optimized procedure for the determination of inorganic antimony species in natural waters using hydride generation atomic fluorescence spectrometry (HG AFS) and continuous flow system. The variables of the hydride generation system, such as pre-reduction time, hydrochloric acid concentration and sodium tetrahydroborate concentration, were evaluated using full factorial design at two levels and Doehlert design. After optimized experimental conditions, the method allowed the determination of antimony with limits of detection and quantification of 9 and 30 ng L-1, respectively. The precision (RSD) of the method was < 5% and the accuracy was confirmed by the analysis of certified reference material (SLRS-4, River water for trace metals). The method was successfully applied for inorganic antimony speciation in water samples collected in Salvador City, Bahia State, Brazil. In mineral water, total Sb concentrations ranged from 0.26 to 0.30 µg L-1, whereas the concentrations of SbIII were below 0.03 µg L-1. On the other hand, in natural surface waters, the quantifiable concentration of total Sb and SbIII ranged from 0.41 to 1.23 µg L-1 and 0.23 to 1.04 µg L-1, respectively. The highest average concentrations of Sb were obtained in regions with the largest urban influence, ratifying the anthropogenic impact in water bodies.