Techniques for the determination of trace element compounds at ppb and ppm levels (in contrast to the determination of the total element concentration) are a prerequisite for the study of the transformations of trace elements in biological systems and the interactions of trace element compounds with biologically important molecules. Two automated high-pressure liquid chromatography (HPLC) systems with element-specific detectors, capable of detecting, identifying and quantitating trace element compounds were developed independently in our laboratories. One of the detectors consists of a Perkin-Elmer graphite furnace atomic absorption spectrometer (GFAA) and a specially adapted autosampler, whereas a Hitachi-Zeeman GFAA, a sample valve, an injector and associated electronics to control the analysis sequence comprise the components of the other detector. The capability of these systems to speciate trace element compounds is demonstrated using arsenite, arsenate, methylarsonic acid (MAA) and dimethylarsinic acid (DMAA) as examples. The separation schemes developed for the four arsenic compounds were used to speciate these compounds in soil extracts and drinking waters. The separation efficiency achieved thus far can very likely be improved through development of better column materials and mobile phases. The work with arsenic compounds clearly shows the great potential of these HPLC-GFAA analytical systems in the area of environmental trace element chemistry, in the field of physiological chemistry and in trace element-related nutritional studies.