Traces of stable isotopes of numerous elements can be nearly simultaneously determined by Inductively Coupled Plasma Mass Spectrometry. Sample liquid is nebulized into a stream of gas and transferred into the plasma, where the sample is atomized and ionized. The plasma core containing the sample ions is extracted from the plasma by a vacuum-system through a combination of two small orifices. A system of electrostatic lenses extracts the ions with positive charge. The extracted ions are separated due to their mass-to-charge ratio in a quadrupole mass filter and detected by a Channel-Electron-Multiplier. Applications are available for water, soil extracts, soil percolates, cell suspensions and digests of plants and soils