FAAS Determination of Lead and Copper in Tea with Microwave Assisted Sample Digestion

The tea sample was digested with mixture of conc.HNO3 and H2O2 (5 to 1),and contents of lead and copper in the sample solution was determined by FAAS.Working conditions of instrument were optimized.Linear relationships between values of absorbance and mass concentration of Pb and Cu were obtained in the ranges of 0.95-3.80 mg·L-1 and 0.108-0.864 mg·L-1,with detection limits (3σ) of 18.3 and 15.9 μg·L-1,respectively.Test for recovery was made by standard addition method,and values of recovery found were in the ranges of 98.8%-102.4% for Pb and 93.3%-100.0% for Cu.