MICROWAVE DIGESTION USING DUAL PTFE CONTAINERS FOR ANALYSIS OF TRACE-ELEMENTS IN SMALL AMOUNTS OF BIOLOGICAL SAMPLES

The analysis of trace elements in biological samples is essential to e xtend our knowledge on human health and disease. Inductively coupled p lasma mass spectrometry (ICP-MS) makes it possible to simultaneously d etermine these elements in trace amounts. Before analysis, however, bi ological samples such as organs and tissues must be liquefied and extr a organic materials must be decomposed by acid digestion. We establish ed a method of microwave digestion using dual PTFE containers to minim ize the amount of samples. Samples (35-45 mg) of standard reference ma terials, bovine liver (1577a, NIST) and fish flesh (MA-A-2, IAEA), wer e weighed in PTFE-PFB vials and a small amount of nitric acid (0.5 ml) mas added. The vials were sealed and two PTFE-PFA vials mere placed i n a PTFE-TFM vessel containing 6 ml of pure mater. Then the vessels we re placed in a rotor and the samples mere digested for 38 min in a mic rowave oven according to a pre-set program. After the program was comp leted, the samples were analyzed by ICP-MS. The determined values of e lements of the microwave-digested samples matched the certified values of the standard reference materials. Therefore, the digestion using d ual containers was successfully applied to small samples.