Development of a new high temperature high pressure flow system for the continuous digestion of biological samples

The development of a new high temperature/high pressure flow system that in corporates resistively heated capillaries for the continuous digestion of v arious samples is presented. The system allows the continuous digestion of samples at temperatures of up to 260 degrees C and a pressure of up to 30 M Pa (300 bar). Aqueous solutions of simple organic compounds such as glucose , as well as slurries of different biological materials, e.g., Bovine Liver , milk or juice, were digested. The determination of the residual carbon co ntent was performed off-line by ICP-OES. Compared with other continuous flo w digestion systems, unusually low residual carbon contents were obtained. For the majority of biological samples digested, the residual carbon conten t was 1-13%, corresponding to a digestion efficiency of 87-99%. The potenti al of the continuous digestion system was illustrated by the digestion of t hree certified reference materials (Dried Whole Animal Blood, Bovine Liver and Tomato Leaves) and subsequent determination of Mn, Cu, Zn and Fe with I CP-OES. Recoveries between 76 and 109% were found. The RSDs ranged from 2.5 (Mn in Tomato Leaves) to 15% (Fe in Dried Whole Animal Blood).