混合正交试验优化微波消解测定沉积物中重金属Pb

[目的]探讨土壤中重金属Pb消解的影响因素。[方法]利用二维平面吸光度等值线变化探讨区域范围内吸光度趋势变化,绘制Pb吸光度分布图,用Minitab 16软件对试验结果进行极差分析和方差分析。[结果]影响Pb消解因素主次排序为HF、HNO_3、HClO_4、燃气流量、HCl、助燃气流量、灯电流和燃烧器高度。优化试验表明,在土壤样品中加入9 mL HNO_3、5 mL HF、3 mL HClO_4经微波消解后,原子吸收分光光度计工作条件如下:Pb波长为217.0 nm,狭缝宽度为1.3 nm,燃烧器高度为4 nm,助燃气流量为2.4 L/min,灯电流为4.0 mA,燃气流量为4.0 L/min。在上述条件下,最优吸光度为0.302。[结论]研究结果可为精确测定土壤中各种重金属吸光度提供理论依据。

Optimization of Determination of Soil Heavy Metal Pb by Mixed Orthogonal Design

[Objective] The aim was to explore the affecting factors for the digestion of soil heavy metal Pb.[Method] The absorbance trend within the area was expressed by change of two-dimensional planar contour for the first time.We used Minitab 16 software to analyze the test results by range and variance method.[Result] The factors affecting Pb digestion was in order of HF,HNO3,HClO4,gas flow,HCl,assistant gas flow,lamp current and combustion height.Test results showed that after adding 9 mL HNO3,5 mL HF and 3 mL HClO4 in soil samples,and microwave digestion,the working conditions of atomic absorption spectrophotometer were as followed: Pb wavelength 217.0 nm,slit width 1.3 nm,burner height 4 nm,assistant combustion gas rate 2.4 L/min,the lamp current 4.0 mA,and propane flow rate 4.0 L/min.Under the above optimal conditions,the optimal absorbance value was 0.302.[Conclusion] The results provide theoretical basis for precisely determining absorbance values of heavy metals in soil.