Determination of trace amounts of molybdenum in water samples by graphite furnace atomic absorption spectrometry with multiple injections and cool down step

The method of multiple injections coupled with graphite furnace and atomic absorption spectrometry is applied to the direct determination of small concentrations of molybdenum in water. The method involves the in situ preconcentration of trace molybdenum in lake water onto a platform made of pyrolitic graphite by multiple injections (up to 5x20 mu l) prior to analysis. In this study, atomization from the L'vov platform was applied, which, in connection with a multiple injection and a cool down step, contributed to increasing sensitivity of the method. The detection limit for molybdenum is 0.072 ng ml(-1). The technique has been applied to the determination of molybdenum in lake waters. (C) 1997 Elsevier Science B.V.