微波消解-石墨炉原子吸收光谱法测定火山灰中的痕量铅铬铜

摘要

火山灰是重要的土壤母质且易风化，铅、铬和铜是其中主要的重金属元素，火山灰风化后不可避免地进入环境中对人体健康造成危害。本研究针对火山灰样品的特点，建立了采用硝酸-氢氟酸微波消解，石墨炉原子吸收光谱法测定火山灰中痕量铅、铬、铜的分析方法。通过实验确定了灰化温度为600℃（ Pb ）、1000℃（ Cr）和800℃（ Cu），原子化温度为1800℃（ Pb和Cu）、2200℃（ Cr）。在优化实验条件下，测定Pb、Cr和Cu的检出限分别为3.50 ng/mL、0.92 ng/mL和1.22 ng/mL，相对标准偏差（ RSD）均低于4％，加标回收率为92.8％~107.0％。本方法快速简便、准确度高、成本低。%Volcanic ash is an important parent material for soil and is easily weathered. Pb,Cr and Cu are the main heavy metals in weathered volcanic ash and are inevitably discharged into the environment and finally harmful to human health. A simple and reliable method for the determination of Pb,Cr and Cu in volcanic ash by microwave digestion combined with Graphite Furnace Atomic Absorption Spectrometry ( GFAAS ) has been proposed. The ashing temperatures are 600℃ for Pb,1000℃ for Cr and 800℃ for Cu. The atomization temperatures are 1800℃ for Pb and Cu,and 2200℃ for Cr. The detection limits of the proposed method are 3. 50, 0. 92 and 1. 22 ng/mL for Pb,Cr and Cu,respectively. The relative standard deviations( RSDs)for eleven replicate analyses(50 ng/mL)of the above three metals are less than 4%,and the spiked recoveries by standard addition are 92. 8% -107. 0%. The proposed method is rapid and convenient with high accuracy and low cost.