WET MINERALIZATION OF ORGANIC MATRICES IN GLASSY-CARBON VESSELS IN A PRESSURE-BOMB SYSTEM FOR TRACE-ELEMENT ANALYSIS

Glassy carbon (Sigradur G®) is thermally stable up to 600° under atmospheric conditions and has proved to be substantially resistant to many decomposition agents at temperatures up to 250°. It can, therefore, substitute for PTFE vessels in a pressure-bomb device for the wet decomposition of organic and inorganic substances with, e.g., nitric, chloric or hydrofluoric acid or mixtures thereof, in the determination of trace elements. The mineralization can be carried out at temperatures up to 50° higher than with PTFE vessels, which are limited to a maximum of 170°. The higher decomposition temperature, which results in a higher oxidation potential, considerably shortens the decomposition time. On account of the lower content of impurities, particularly of Hg, Ag, Bi, Cd, Se, Te and Sb, the results are more accurate than those obtained with PTFE vessels, if these elements are to be determined in the ng/g range in the resulting solution. © 1979.