高级检索

    全自动石墨消解-电感耦合等离子体质谱法测定土壤中7种重金属元素的含量

    Determination of 7 Heavy Metal Elements in Soil by Inductively Coupled Plasma Mass Spectrometry with Automatic Graphite Digestion

    • 摘要: 取0.200 0 g土壤样品置于50 mL聚四氟乙烯消解管中,用少量水润湿,以4.5 mL盐酸、1.5 mL硝酸、3 mL氢氟酸和1 mL高氯酸为消解体系,于全自动石墨炉消解仪中按照程序进行消解,取出冷却10 min,用5%(体积分数)硝酸溶液定容至25 mL,分取2.5 mL,用2%(体积分数)硝酸溶液定容至25 mL,与10 μg·L−1185Re、103Rh混合内标溶液在线混合后,采用电感耦合等离子体质谱法测定砷、铜、铅、锌、铬、镉、镍等7种重金属元素的含量。结果表明:7种重金属元素的质量浓度在一定范围内和对应的信号强度与内标信号强度比呈线性关系,检出限(3s)为0.008~0.07 mg·kg−1。对土壤标准样品GSS-29、GSS-31、GSS-34进行准确度和精密度试验,测定值的相对误差的绝对值均小于7.0%,除镉元素外的6种重金属元素测定值的相对标准偏差(n=6)均小于5.0%;与传统的电热板消解法相比,本方法的准确度和精密度更优。

       

      Abstract: The soil sample (0.200 0 g) was taken and placed in a 50 mL-polytetrafluoroethylene digestion tube, and wetted with a small amount of water. 4.5 mL of hydrochloric acid, 1.5 mL of nitric acid, 3 mL of hydrofluoric acid and 1 mL of perchloric acid were used as the digestion system, and the mixture was digested by a automatic graphite furnace digester according to the program. The mixture was taken and cooled for 10 min, and made its volume up to 25 mL with 5% (volume fraction) nitric acid solution. An aliquot (2.5 mL) of the solution was taken, made its volume up to 25 mL with 2% (volume fraction) nitric acid solution, and mixed well online with 10 μg · L−1 of 185Re and 103Rh internal standard solution, in which 7 heavy metal elements, including arsenic, copper, lead, zinc, chromium, cadmium, nickel were determined by inductively coupled plasma mass spectrometry. As shown by the results, linear relationships between the ratios of the corresponding signal intensity to the internal standard signal intensity and mass concentrations of 7 heavy metal elements were kept in definite ranges, with detection limits (3s) in the range of 0.008-0.07 mg · kg−1. Tests for accuracy and precision on the soil standard samples GSS-29, GSS-31 and GSS-34 were carried out, and the absolute values of the relative errors of the determined values were less than 7.0%, and RSDs (n=6) of the determined values of the 6 elements except cadmium were less 5.0%. Compared with the traditional electric hot plate digestion method, the accuracy and precision of this method were better.

       

    /

    返回文章
    返回