An analytical scheme that uses inductively coupled argon plasma emission spectroscopy (ICAP) and hydride evolution atomic-absorption spectrometry (HEAA) for the determination of trace elements in plant and animal tissues has been evaluated. The scheme incorporates the ion-exchange procedure of Kingston et al., which uses Chelex 100 resin to concentrate trace elements and remove potentially interfering alkali and alkaline earth metals. The separation procedure is included in a scheme designed to maximise the number of analyte metals that can be determined from a single digestion of a biological matrix. Acid-digested samples are divided into two fractions. One fraction (5% of the total) is measured directly by ICAP for alkali and alkaline earth metals and phosphorus and for transition metals such as iron and manganese, which are not well behaved on the resin. The other fraction (95% of the total) is subjected to the separation procedure whereby a number of biologically important trace elements, including cadmium, copper, molybdenum, nickel, vanadium and zinc, are initially sequestered by the resin, and then stripped into a small volume of dilute nitric acid for ICAP measurement of the “matrix-free” analytes. Arsenic, selenium and antimony, which are not retained by the resin, are collected with the initial column effluent, acidified and determined by HEAA. The reliability of the scheme is influenced by the nature of the acid digestion procedure used to oxidise the organic matrix. The scheme was tested by analysis of ten National Bureau of Standards biological reference materials.