GF-AAS Determination of Traces of Lead in Vegetables with Micro-Wave Assisted Sample Digestion

The pretreated sample in dry powder was digested with conc.HNO3 and H2O2 in a microwave oven.The sample solution was evaporated to a volume of 1~2 mL,and diluted to 10 mL in a volumetric flask.An appropriate aliquat was taken for the AAS determination.Optimum working conditions of the instrument was described in detail.Ammonium nitrate and potassium hydrogen phosphate were used as matrix modifier and the self-absorption background correction was used in the determination.Linearity was kept in the range of 0-50.0 μg of lead in 1 liter of solution,with a detection limit of 1.6 μg·L-1.Tests for recovery were made with 10 kinds of vegetable samples,the values of recovery obtained were in the range of 92.2%-108.2%.