微波消解石墨炉原子吸收光谱法测定蔬菜中痕量铅

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

经清洗、粉碎并烘干的试样在微波炉中用浓硝酸及过氧化氢消化。所得溶液蒸缩至1-2 mL后定容为10 mL,分取适量作AAS测定。以自吸背景校正方式,在硝酸介质中,K2HPO4为基体改进剂,直接用石墨炉原子吸收光谱法测定蔬菜中铅。铅的质量浓度在0-50.0μg·L^-1范围内呈线性,检出限为1.60μg·L^-1,回收率为92.2%-108.2%。

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. 0μg of lead in 1 liter of solution, with a detection limit of 1.6μg·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%.