原子荧光法测定土壤和沉积物中汞元素的混合酸消解方法研究

Study on Mixed Acid Digestion Method for Determination of Mercury in Soil and Sediment by Atomic Fluorescence

利用酸组分试剂的不同组合研究测定土壤和沉积物中汞元素的消解条件,并探讨在不同土壤和沉积物样品之间所产生的差异,针对酸组分对不同样品的差异确定土壤样品中差异成分的适合条件。结果表明:当样品质量为(0.2000±0.50%)g时,土壤和沉积物消解的酸组分最佳组合为逆王水法的盐酸:硝酸:过氧化氢=1:3:1,各消解法的处理效率(n=5):水浴法时间可缩短为1.0 h,准确度(回收率)达93.1%,精密度(RSD)为1.35%;电热板法因处理时间长且回收率不佳,不建议采用(准确度为80.5%,RSD为13.3%);微波法处理的总时间为1.0 h,回收率为92.4%,但精密度稍差为9.32%,因此选用水浴法进行真实样品测定。此优化的消解方法能直接应用于多种真实样品的前处理,并能简便地利用同一酸组分条件快速测定土壤和沉积物类型的样品,为环境污染监测检测行业提供参考依据。

The digestion conditions of mercury in soil and sediment were studied by using different combinations of acid component reagents,and the differences in different soil and sediment samples were discussed.The suitable conditions for different components in soil samples were confirmed according to the differences of acid components in different samples.The results show that under the condition of(0.2000±0.50%)g of the sample,the best combination of acid components of soil and sediment digestion is hydrochloric acid:nitric acid:hydrogen peroxide=1:3:1.The treatment efficiency of each digestion method is(n=5):the time of water bath method can be shortened to 1.0 h,the recovery rate of accuracy is 93.1%,and the precision RSD is 1.35%;the electrothermal plate method is not recommended due to long treatment time and poor recovery(accuracy is 80.5%,RSD is 13.3%);the total time of microwave treatment is 1.0 h,recovery is 92.4%,but the precision is slightly worse at 9.32%.Therefore,the water bath method is selected for the determination of real samples.This optimized digestion method can be directly applied to the pretreatment of many real samples,and can be used to quickly correspond the soil and sediment samples with the same acid composition conditions, providing a reference for environmental pollution monitoring and detection industry.