A heated graphite furnace atomization system is described for use in atomic absorption spectrometry. The furnace is operated continuously, and desolvated sample aerosol is introduced continuously. Graphite components are coated with a layer of pyrolytic graphite for reduced porosity and increased durability. Gradual deterioration due to oxidation is completely compensated for by a continuous pyrolysis treatment. With continuous sample introduction and furnace operation, several benefits are realized. Reproducibility of measurement is improved several-fold. A relatively simple furnace power supply can be used. Transient signals need not be dealt with. Steady-state conditions for the vaporization and atomization processes prevail, and these can be investigated under controlled conditions and temperatures. Thus, matrix effects can be studied in detail and the results of these studies used to advantage.The earlier nonflame atomization systems which employed continuous sample introduction, such as the dc arc plasma jet (1, 2), rf plasma torch (3, 4), and cascade arc (5, 6) have proved to be effective primarily in atomic emission spectroscopy (6, 7). Woodriff and Ramelow (S) first used continuous sample introduction with a graphite furnace for atomic absorption measurements. Recently, an electricallyheated platinum tube furnace has been used by Black et al. (9) for atomic fluorescence spectrometry, and Murphy et al. (10) developed a graphite tube furnace in this laboratory for the same purpose. This furnace system has been used with continuous sample introduction for atomic fluorescence spectrometry with a single continuum source and is described elsewhere (11).