FAAS Determination of Trace Amount of Pb(II) in Vegetables After Separation and Preconcentration with Humic Acid/Attapulgite Compound Material

The vegetable sample was dissolved in a mixed solution of HNO3 and H2O2(7+4).Trace amount of Pb(Ⅱ) in the sample solution was separated and preconcentrated on humic acid/attapulgite compound material(HACM),and eluted from FACM with 1.5 mol·L-1 nitric acid-methyl isobutyl ketone at the flow-rate of 10.0 mL·min-1.The dynamic adsorption capacity of Pb(Ⅱ) on HACM obtained was 40.98 mg·g-1.Linear relationship between values of absorbance and mass concentration of Pb(Ⅱ) was obtained in the range of 0.32-5.12 mg·L-1,with detection limit(3σ) of 0.32 μg·L-1.The proposed method was used in the analysis of vegetable samples,and recovery was tested by standard addition method giving values of recovery in the range of 96.2%-104.4% with RSD′s(n=6) less than 2%.