Simultaneous determination of arsenic and antimony in spring water by coprecipitation with zirconium hydroxide and XRF analysis

The method described has the advantages of easy preparation and rapid measurement of samples as compared with the other method, and enables the simultaneous determination of arsenic and antimony. One milliliter of zirconium oxychloride solution (10 mg Zr/ml), a coprecipitant, was added to 100 ml sample solution, then pH of the solution was adjusted to 9 with ammonia water. After collected on a Toyo No. 5C filter paper, the precipitate was dried in a desiccator for XRF analysis. Precipitation recoveries of arsenic(III) and antimony(III) in spring water with zirconium hydroxide were sufficient, while those of arsenic(V) and antimony (V) were not due to the interference of foregin ions. Therefore, arsenic(V) and antimony(V) were reduced to arsenic(III) and antimony(III) by adding 1 g potassium bromide and 1 ml hydrochloric acid to the sample and boiling it at 80 °C for 1 h, so that the sufficient recoveries were obtained. The linear range of calibration curves for arsenic and antimony by this method was within 200μg. The limits of detection were 0.3 μg for arsenic and 6.1 μg for antimony in case of 100 ml sample volume. The analytical results of arsenic and antimony in spring waters at several sites in Japan by this method were in good agreement with those obtained by the hydride generation AAS.