EVALUATION OF THE USE OF MICROWAVE-OVEN SYSTEMS FOR THE DIGESTION OF ENVIRONMENTAL-SAMPLES

In most chemical analyses for inorganic determinations in environmenta l matrices the sample is physically destroyed by dissolution, calcinat ion etc. These digestion procedures have to be validated in order to e nsure that no contamination and/or losses have occurred which could af fect the accuracy of the final results obtained; this validation can b e made by using certified reference materials (CRMs). In the recent pa st, microwave digestion procedures have been developed and have been s hown to offer the benefits of rapid sample preparation and reduced con tamination risks; however, an incomplete dissolution was suspected in some cases, e.g. in interlaboratory exercises, for the analysis of org anic matrices. The aim of this study was to test microwave digestion p rocedures for different environmental CRMs and to evaluate the suitabi lity of these methods for the determination of some trace elements. Th e effects of chemical species (As, Hg and Se-species) on the total ele ment recovery after digestion are discussed.