双硫腙显色分光光度法测定校园土壤中微量铅的含量

Detection of the Content of Lead in Soil by Spectrophotometry

采用以双硫腙为显色剂的分光光度法测定土壤中铅的含量。将土壤消解,使其中的金属铅与双硫腙形成显色络合物,在最大波长517 nm处测定吸光度,并探讨了显色时间、p H显色剂用量对测定结果的影响。铅浓度在0~1 g/m L范围内符合郎伯-比尔定律,制得线性回归方程为y=0.092 8x+0.159 2,线性回归系数R2=0.999 1,相关性较好。结果表明绿化带土壤铅含量为42.17 mg/kg,道路一侧土壤铅含量为77.73 mg/kg,基本没有污染。此法适用于土壤中铅的测定。

The content of lead in soil was detected by spectrophotometry with dithizone as color reagent. The soil was digested to make lead in soil and the dithizone a color complex. The absorbance was measured at the maximum wavelength of 517 nm and the effects of the coloration time, and the amount of the color reagent on the measurement were investigated. The concentration of lead complied with the Lambert-Beers Law when it was in the range of 0 - 1 μg/m L. Then the linear regression equation, and the linear regression coefficientwith good correlation were obtained. The research results show that only slight pollution exits as the lead content in the soil of the green belt is 42.17 mg/kg, and the lead content in soil along a major road is 77.73 mg/kg. This method is applicable to the detection of lead in soil.