Direct ICP-AES Determination of Trace Impurities in Silicon Dioxide Using Fluorinating Electrothermal Vaporization with Slurry Sampling

Based on the selective volatilization taking place between the matrix and the analyte in the graphite furnace, a new method for a direct ICP-AES determination of trace impurities in SiO2 powder using electrothermal vaporization (ETV) as a slurry-sampling technique is described. A polytetrafiuoroethylene (PTFE) emulsion is used as a fluorinating reagent to promote the vaporization of impurity elements from SiO2 powder. The fluorinating vaporization and transportation behaviors, the matrix effects and the particle-size effects have been investigated systematically. When the sampling volumes are 10 μl, the detection limits of Cu, Cr, Fe and Ti are 1.05,1.58, 1.06 and 0.9 μgl-1, respectively, and the RSDs are in the range of 1.9-4.1%. The proposed method has been applied to analyze SiO2 powder without any chemical pretreatment. The determined values are in good agreement with the results obtained by using acid decomposition- pneumatic nebulization ICP-AES.