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    恒温振荡提取-电感耦合等离子体质谱法测定土壤中6种重金属元素可提取态的含量

    Determination of 6 Extractable Heavy Metal Elements in Soil by Inductively Coupled Plasma Mass Spectrometry with Constant Temperature Oscillation Extraction

    • 摘要: 提出了恒温振荡提取-电感耦合等离子体质谱法(ICP-MS)测定土壤中铬、镍、铜、锌、镉、铅等重金属元素可提取态含量的方法。将土壤样品风干,过2 mm尼龙筛。取过筛后的土壤样品10.0 g置于具塞离心管中,加入100 mL 0.01 mol·L−1氯化钙溶液,置于立式智能精密摇床中,设置提取温度为(20±2) ℃,水平振荡速率为(180±20) r·min−1,提取时间为120 min。提取后离心、过滤,收集续滤液至10 mL比色管中,在积分时间0.5 s、碰撞池模式条件下,以内标72Ge校正53Cr、60Ni、63Cu、66Zn,103Rh校正114Cd,185Re校正208Pb,采用ICP-MS测定其中6种重金属元素可提取态的含量。结果表明,铬、镍、铜、锌、镉、铅元素的质量浓度均在一定范围内与所对应的信号强度与内标信号强度比呈线性关系,检出限(2.764s)分别为0.076,0.075,0.074,0.15,0.010,0.050 mg·kg−1。方法用于国家标准物质的分析,对于认定值在检出限以上的元素,其测定值与认定值基本一致,高于检出限的测定值的相对标准偏差(n=6)均不大于5.0%。

       

      Abstract: A method for the determination of extractable heavy metal elements including chromium, nickel, copper, zinc, cadmium, and lead in soil by inductively coupled plasma mass spectrometry (ICP-MS) with constant temperature oscillation extraction was proposed. The soil sample was dried naturally and passed through a 2 mm nylon sieve. 10.0 g of the sieved soil sample was taken and placed into a stoppered centrifuge tube. 100 mL of 0.01 mol·L−1 calcium chloride solution was added and the mixture was placed in a vertical intelligent precision shaker. The extraction temperature was set at (20±2) ℃, with the horizontal oscillation speed of (180±20) r·min−1, and the extraction time of 120 min. After extraction, the mixture was centrifuged and the supernatant was filtered. The resulting filtrate was collected into a 10 mL colorimetric tube, in which 6 extractable heavy metal elements were determined by ICP-MS under the conditions of integration time of 0.5 s and collision pool mode,using internal standard 72Ge to correct 53Cr,60Ni,63Cu and 66Zn, as well as 103Rh to 114Cd and 185Re to 208Pb. As shown by the results, linear relationships between the corresponding signal intensity and the internal standard signal intensity ratios and mass concentrations of chromium, nickel, copper, zinc, cadmium, and lead elements were found in definite ranges, with detection limits (2.764s) of 0.076, 0.075, 0.074, 0.15, 0.010, 0.050 mg·kg−1, respectively. The method was used for the analysis of national standard substances. For elements with the certified values above the detection limits, the determined values were basically consistent with the certified values. RSDs (n=6) of the determined values of elements above the detection limits were not more than 5.0%.

       

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