LIQUID-CHROMATOGRAPHY AND MASS-SPECTROMETRY FOR THE SPECIATION OF ARSENIC ANIMAL FEED ADDITIVES

A number of analytical techniques have been investigated for the deter mination 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 relativel y new technique, shows a number of advantages for these analyses, espe cially when interfaced to mass spectrometers. Improved limits of detec tion, low solvent consumption, reduced amounts of stationary phase, as well as flow-rates easily accommodated by continuous-flow liquid seco ndary ion mass spectrometry and direct liquid introduction mass spectr ometry, are some of the advantages we have observed when fabricating a nd using these columns. The off-line combination of micro liquid chrom atography and electrothermal atomic absorption spectrometry improves t he limit of detection for arsenic and shows potential for on-line coup ling. Further use of the methods developed here may allow for a more d etailed understanding of the fate and interactions of arylarsenicals i n biological and environmental systems.