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[目的]建立动态三磁场塞曼效应背景校正石墨炉原子吸收法测定土壤中镉含量的分析方法。[方法]土壤样品经风干除杂,研磨过筛,微波消解后,以磷酸氢二铵为基体改进剂,优化塞曼分裂条件,动态三磁场背景校正模式进行测定。[结果]以2.0μg/L为浓度分界点,仪器自动给出各个浓度在二磁场和三磁场模式下的光密度值,其中0.0~2.0μg/L浓度范围采用二磁场背景校正模式,标准曲线方程为?=3.98×10~(-2)x+5.05×10~(-3),r=0.996 8,特征浓度0.11(μg/L)/1%y;在2.0~50.0μg/L浓度范围采用三磁场背景校正模式,标准曲线方程为?=(-9.7×10-5+1.42×10~(-2)x)/(1+2.36×10~(-2)x),r=0.998 1,特征浓度0.31(μg/L)/1%y,回收率在90.0%~103.0%之间,相对标准偏差(RSD)在3.2%~4.2%之间。[结论]本方法操作简便,准确度、精密度好,扩展了镉测定的线性范围,满足浓度不一的土壤中镉的测定,适用于环境调查土壤中镉含量测定。
[Objective] The research aimed to establish a dynamic three-magnetic Zeeman effect background correction method for the determination of cadmium in soil by graphite furnace atomic absorption spectrometry. [Method] The soil samples were air-dried, ground, sieved and microwave-digested. The diammonium hydrogen phosphate was used as matrix modifier to optimize Zeeman splitting conditions and dynamic three-magnetic background correction mode. [Result] With the concentration of 2.0μg / L as the demarcation point, the instrument automatically gave the optical density value of each concentration in two magnetic field and three magnetic field modes. The two magnetic field background correction mode was adopted in the concentration range of 0.0-2.0μg / L, the standard curve The equation is: = 3.98 × 10 -2 x + 5.05 × 10 -3, r = 0.996 8, the characteristic concentration is 0.11 (μg / L) / 1% y; at the concentration range of 2.0-50.0 μg / L The three-field background correction mode is adopted. The standard curve equation is: (= 9.7 × 10-5 + 1.42 × 10 -2 × (1 + 2.36 × 10 -2) x), r = 0.998 1 , The characteristic concentration was 0.31 (μg / L) / 1% y, the recoveries ranged from 90.0% to 103.0% and the relative standard deviations (RSDs) ranged from 3.2% to 4.2%. [Conclusion] The method was simple, accurate and accurate. It extended the linear range of determination of cadmium and satisfied the determination of cadmium in soils with different concentrations. It is suitable for the determination of cadmium in soils by environmental survey.