ICP MS Determination of 17 Elements in Sludge from Petroleum Refineries

Seventeen elements (including Ag, As, Ba, Be, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Tl, V, Zn and Hg) in sludge from petrorefineries were determined by ICPMS. A portion of the sludge sample was placed in a crucible and treated preliminarily first by drying at 100 ℃ (30 min), then by ignition at 300 ℃ (20 min) and at 800 ℃ (2 h) to ash the sludge for reducing or elimination of interference due to organic substances. An aliquot of 0.1 g of the ash was taken and placed in the PTFE digesting container and digested with the acid mixture of HNO3 and H2O2 in a microwave digestor. The solution obtained was diluted to an appropriate concentration and used for ICPMS analysis. Values of detection limit (3s/k) for the 17 elements were found in the range of 0.4-215 μg·L-1. Precision and recovery were tested, giving values of RSD′s (n=8) in the range of 2.1%-6.5%, and of recovery in the range of 80.1%-106%.