Liquid chromatography and mass spectrometry for the speciation of arsenic animal feed additives

A number of analytical techniques have been investigated for the determination of arsenic animal feed additive compounds. More specifically, liquid chromatography methods have been developed for the separation of these arsenicals. Micro liquid chromatography, which is a relatively new technique, shows a number of advantages for these analyses, especially when interfaced to mass spectrometers. Improved limits of detection, low solvent consumption, reduced amounts of stationary phase, as well as flow-rates easily accommodated by continuous-flow liquid secondary ion mass spectrometry and direct liquid introduction mass spectrometry, are some of the advantages we have observed when fabricating and using these columns. The off-line combination of micro liquid chromatography and electrothermal atomic absorption spectrometry improves the limit of detection for arsenic and shows potential for on-line coupling. Further use of the methods developed here may allow for a more detailed understanding of the fate and interactions of arylarsenicals in biological and environmental systems.