大气颗粒物中铅的序列提取与分析表征

Characterization of Lead in the Atmospheric Aerosols by Sequential Extraction Procedures Coupled with Graphite Furnace AAS

用石英纤维滤膜采集大气颗粒物样品,采用序列提取的方法把铅的总量分成环境可迁移态、碳酸盐和氧化物态、有机质和残渣态3个分量,用石墨炉原子吸收分光光度法测定铅的浓度,仪器检出限为1μg/L。对实际大气颗粒物样品进行序列提取,5份平行的序列提取3个分量测定及加和值的RSD分别为7.1%、3.3%、7.3%、5.0%。该样品三级序列提取的加和值(756μg/g)约为总量测定(738μg/g)的102%,两组数据一致性良好,且环境可迁移态、碳酸盐和氧化物态、有机质和残渣态的铅分别为加和值的64%、17%和20%。对几种典型的铅污染源排放样品进行序列提取和分析测定,不同源排放样品的形态特征各有特点,说明该序列提取的方案是可行的,达到了将不同形态的铅化合物分开的目的。

In this study, for atmospheric aerosol samples collected on quartz filters, sequential extraction procedures were used to divide the total lead content into three fractions, i.e., the environmentally mobile fraction, the fraction bound to carbonate and oxide, and the fraction bound to silicate and organic matter, followed by graphite furnace atomic absorption spectrometic (AAS) measurements, with a detection limit of 1 μg/L for lead. Duplicated analyses (n=5) with sequential extraction procedures for real atmospheric aerosol samples presented relative standard deviation of 7.1%, 3.3%, 7.3%, 5.0% respectively for the three fractions and their sum. The sum of the three fractions, 756 μg/g, was in consistence with the total lead content, 738 μg/g. The environmentally mobile fraction, the fraction bound to carbonate and oxide, and the fraction bound to silicate and organic matter, accounted for 64%,17% and 20% of the sum, respectively. It was also determined by using sequential extraction procedures and graphite furnace AAS method for samples from selected lead emission sources. It seems that sequential extraction procedures are feasible and useful to differentiate various lead species.