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%.