Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) with smart heater pre-digestion and microwave digestion was applied to determine lead, cadmium, chromium, copper and zinc in kelp. We compared the results obtained for the contents of the five metal elements by an external standard method and an internal standard method. The results indicate that the internal standard method was better and exhibited a linear range of 0－50 μg/L for each metal element (r ＞ 0.9998) with a RSD less than 5%. The limits of detection for these metal elements were 0.3－1.9 μg/kg. It allowed simple, rapid, sensitive and accurate determination of heavy metal elements in kelp.

Key words: kelp, heavy metal elements, microwave digestion, inductively coupled plasma mass spectrometry