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目的探讨微波消解-石墨炉原子吸收光谱测定土壤中铅和镉的方法。方法土壤样品研磨过100目筛,用硝酸-氢氟酸-盐酸混合消解液微波消解后,用石墨炉原子吸收光谱测定土壤中的铅和镉。结果铅浓度在5.0~40.0μg/L范围内呈良好线性关系,回归方程为y=0.008 51x+0.017 3,相关系数r=0.999 6;镉浓度在0.50~4.00μg/L范围内呈良好线性关系,回归方程为y=0.105 51x+0.006 9,相关系数r=0.999 1。铅的定量限为0.600 mg/kg,检出限为0.200 mg/kg;镉的定量限为0.060 mg/kg,检出限为0.020 mg/kg。铅加标回收率为91.0%~102.0%,相对标准偏差为3.7%~5.2%;镉加标回收率为90.0%~101.0%,相对标准偏差为3.4%~5.4%。结论该方法简便、快速,基体干扰少,结果准确,适用于土壤中铅、镉含量的测定。
Objective To investigate the method of microwave digestion - graphite furnace atomic absorption spectrometry for determination of lead and cadmium in soil. Methods Soil samples were ground through a 100-mesh sieve. After microwave digestion with nitric acid-hydrofluoric acid-hydrochloric acid digestion solution, Pb and Cd in soils were determined by graphite furnace atomic absorption spectrometry. Results The results showed that there was a good linear relationship between the concentration of Pb in the range of 5.0 ~ 40.0μg / L, the regression equation was y = 0.008 51x + 0.017 3, the correlation coefficient was 0.999 6, and the linearity was 0.50 ~ 4.00μg / L , The regression equation is y = 0.105 51x + 0.006 9, the correlation coefficient r = 0.999 1. The limit of quantification for lead was 0.600 mg / kg, the limit of detection was 0.200 mg / kg, the limit of quantification for cadmium was 0.060 mg / kg and the limit of detection was 0.020 mg / kg. The recoveries of spiked lead ranged from 91.0% to 102.0% with relative standard deviations of 3.7% -5.2%. The recoveries of cadmium were 90.0% -101.0% with relative standard deviations of 3.4% -5.4%. Conclusion The method is simple, rapid, less interference matrix, the results are accurate, suitable for the determination of lead and cadmium in soil.