A description is given of the experimental arrangement for thermospray nebulization of discrete liquid samples (100 microl) into an inductively coupled plasma-mass spectrometer (ICP-MS). The determination of ultratrace levels of platinum in environmental and biological materials is described. This method comprises an off-line sample enrichment by adsorptive chromatography, elution with ethanol and subsequent analysis of the evaporated eluate. The quantification of the concentration was performed with isotope dilution. The recovery, precision, accuracy and detection limit of the method are discussed.