Determination of trace elements in carbonaceous samples by graphite furnace atomic absorption spectrometry: Microwave digestion versus slurry sampling

The determination of chromium, copper, manganese, nickel and vanadium in ca rbonaceous samples by slurry introduction graphite furnace atomic absorptio n spectrometry and after microwave assisted digestion are compared. Paramet ers such as atomization and pyrolysis temperatures, and surfactant concentr ation as well as the homogenization procedure were optimized. The slurries were prepared by mixing adequate amounts of the pulverized samples with 0.0 5% Triton X-100, sonicating for, at least, 40 seconds during the preparatio n to separate aggregates and for 20 seconds immediately before being autosa mpled. It was not necessary to use modifiers and calibration against aqueou s standards was possible for all the elements. Coke, graphite and certified coal samples were analyzed, and no significant difference was observed usi ng both procedures. Good agreement between found and certified values was o btained.