Tungsten has been determined by atomic absorption spectrometry at 400.9 nm using a dinitrogen oxide-acetylene flame in an alkaline medium with potassium persulphate as releasing agent, which causes an enhancement of around 75% in the tungsten signals. The medium being alkaline, the cations generally associated with tungsten, such as chromium(III), iron(III), vanadium(IV), manganese(II), cobalt(II), nickel(II), titanium(IV), calcium(II) and magnesium(II), are separated as hydroxides and hence have no effect. Aluminium(III), vanadium(V), molybdenum(VI) and chromium(VI), which remain in solution along with tungsten, do not interfere. The method has been applied to the analysis of a variety of alloys, ferrotungsten, cobalt- and nickel-base alloys, tungsten ores and concentrates.