Trace Analysis and Speciation for Arsenic Anions by HPLC-Hydride Generation Inductively Coupled Plasma Emission Spectroscopy

Abstract

High performance liquid chromatography (HPLC) has already been successfully interfaced with inductively coupled plasma (ICP) emission spectroscopy for arsenic analysis and speciation. However, in many instances the overall minimum detection limits (MDLs) are inadequate for many environmental type samples. Arsine generation in a continuous, on-line fashion has been shown to provide for significantly improved MDLs by direct-ICP approaches. This hydride generation-ICP (HY-ICP) derivatization approach has now been successfully interfaced with paired-ion, reversed phase HPLC. This provides a doubly hyphenated technique, namely HPLC-HY-ICP in order to perform true metal/nonmetal speciation. Such methods of arsenic speciation have now been perfected with regard to minimum detection limits, linearity responses over several orders of magnitude, separation of various arsenic species from possible sample interferences, and related analytical matters. The final approaches have been applied both to spiked water samples, as well as to actual environmental drinking water supplies from the New England region. These results demonstrate an ability to qualitatively and quantitatively speciate for arsenate and arsenite at levels ranging from 50 ppb and above in each species. The ability to speciate drinking water supplies (wells) is also I demonstrated by these overall application results.