Abstract: A system is described in which a graphite furnace electrothermal vaporization device is employed for the introduction of microlitre liquid sample into an inductively coupled argon plasma. The technique provides a picogram detection limit and an adequate precision with a relative standard deviation of 4%. Mechanism of analyte condensation in transport process is explored. As an application, the technique combined with DDTC/CCl₄ extraction is used to enrich and determine non- rare earth impurities in highly pure La₂O₃.

Key words: Electrothermal sample introduction, Inductively coupled plasma, Optical emis-sion spectrometry