This method consists of two approaches: isotope dilution mass spectrometry (IDMS) for the determination of total metals and speciated isotope dilution mass spectrometry (SIDMS) for the determination of elemental species. This method is applicable to the determination of total metals and metal species at sub µg/L levels in water samples or in waste extracts or digests. In general, elements that have more than one available stable isotope can be analyzed by IDMS. SIDMS may require more isotopes of an element, depending on the number of interconvertable species. The current method is applicable to the following elements.