Arsenic speciation using high performance liquid chromatography-inductively coupled plasma-mass spectrometry

摘要

A method has been developed by Argonne National Laboratory to identify and quantify As(III), As(V), and organoarsenic compounds in environmental samples. A arsenic species were separated by reversed-phase, ion-pairing, HPLC using a microbore Inertsil-ODS(trademark) column. Only 1 microL of sample was injected on the column, and the mobile phase flow rates were typically on the order of 40 microL/min. The HPLC mobile phase was a mixture of methanol and tetrabutylammonium hydroxide (TBAH), and the column effluent was introduced into an ICP-mass spectrometer using direct injection nebulization. Detection limits of less than 1 pg As (as injected on the column) were easily obtained for each arsenic species. The effect of changes in mobile phase composition and ICP-MS conditions will be described, as well as quality control measures, e.g., the use of surrogates, internal standards, and matrix spikes. Precision and accuracy information will be presented from the analysis of aqueous standards and soil extracts that were spiked with arsenic oxide (As(III)), sodium arsenate (As(V)), dimethylarsinic acid (DMAA), or chlorovinyl arsenious acid (CVAA).