OPEN-FOCUSED MICROWAVE-ASSISTED DIGESTION FOR THE PREPARATION OF LARGE MASS ORGANIC-SAMPLES

Microwave-assisted wet digestions of large sample masses (up to 10 g) of biological materials and hydrocarbon-based oil were successfully ac complished at atmospheric pressure using an open-focused system, The p er cent. residual carbon contents (RCC) of the resulting solutions, tr ace element recovery and extent of contamination (magnitude of the bla nk) were used to characterize the performance of the methodology, A Pr olabo Maxidigest M 401 unit, fitted with a modified reaction vessel, w as used to solubilize samples of National Research Council of Canada ( NRCC) certified reference materials TORT-I and LUTS-1 (Lobster Hepatop ancreas) as well as Conostan 75 base oil, using either HNO3 or a mixtu re of HNO3-H2SO4. Digestion efficiency increased with increased digest ion time and sample mass (15% RCC with 0.25 g sample, 2% RCC with 8 g sample), The minimum spike recovery of added elements (As, Cd, Cr, Co, Cui Fe, Pb, Mn, Ni, Se, Sr and Zn) was 94.5% (Sr) and averaged 99% in HNO3 and 97% in the mixed acid. Certified reference values for trace element content were achieved for TORT-1 and LUTS-1.