FAAS Determination of 4 Heavy Metals in Sludge of Certain City Proper

Samples of sludge were air-dried, ground to size of 150 μm, and finally dried at 105 ℃ for 4 h. The dried sample was digested with mixed acid of HNO3-HF-HClO4, and the sample solution was made up to 250 mL in a volumetric flask. A aliquot of 5.00 mL was taken and diluted quantitatively to 100 mL with HNO3 (0.2+99.8) and used for FAAS determination of Mn, Cu, Cd and Pb under the prescribed conditions. Detection limits (2s) found for the 4 elements were 0.006 5, 0.001 6, 0.001 9 and 0.020 7 mg·L-1 respectively. Tests for recovery were made and the results obtained were in the range of 92.3%-98.6%.