Selective determination of trace arsenic and antimony species in natural waters by gas chromatography with a photoionization detector

Abstract

AbstractTraces amounts of arsenic and antimony in water samples were determined by gas chromatography with a photoionization detector after liquidnitrogen cold trapping of their hydrides.The sample solution was treated with sodium hydroborate (NaBH4) under weak‐acid conditions for arsenic(III) and antimony(III) determination, and under strong‐acid conditions for arsenic(III+V) and antimony(III+V) determination.Large amounts of carbon dioxide (CO2) and water vapor obscured determination of arsine and stibine. Better separation from interference could be achieved by removing CO2 and water vapor in two tubes containing sodium hydroxide pellets and calcium chloride, respectively.The detection limits of this method were 1.8 ng dm−3 for arsenic and 9.4 ng dm−3 for antimony in the case of 100‐cm3 sample volumes. Therefore, it is suitable for determination of trace arsenic and antimony in natural waters.