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    腐植酸/凹土复合材料分离富集-火焰原子吸收光谱法测定蔬菜中痕量铅(Ⅱ)

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

    • 摘要: 蔬菜试样用硝酸-过氧化氢(7+4)溶液溶解后,以腐植酸/凹土复合材料(HACM)分离富集样品溶液中的痕量铅(Ⅱ),1.5 mol·L-1硝酸-甲基异丁酮溶液进行淋洗分离,流量为10.0 mL·min-1,采用火焰原子吸收光谱法测定蔬菜中痕量铅(Ⅱ)。在优化的试验条件下,HACM对铅(Ⅱ)的动态吸附容量为40.98 mg·g-1。铅(Ⅱ)的质量浓度在0.32~5.12 mg·L-1范围内与吸光度呈线性关系,方法的检出限(3σ)为0.32 μg·L-1。方法用于分析蔬菜样品,并用标准加入法做回收试验,测得回收率在96.2%~104.4%之间,测定值的相对标准偏差(n=6)均小于2%。

       

      Abstract: 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%.

       

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