Investigations on the use of chemical modifiers for the direct determination of trace impurities in Al_2O_3 cermic powders by slurry electrothermal evaporation coupled with inductively-coupled plasma mass spectrometry (ETV-ICP-MS)

摘要

The direct determination of trace impurities in Al_2O_3 ceramic basic powders by ICP-MS using electrothermal evaporation (ETV) with slurry sampling has been investigated. To increase interference-free analyte volatilization, the use of the palladium-group modifiers (PGM) IrCl_3,Pd(NO_3)_2,and PdCl_2 for the determination of Ca,Fe,Ga,Mg,Mn,Na,Ni,and V in Al_2O_3 powders was studied. Their role,whioch in ETV-KCP-MS and ETV-ICP-OES is to stabilize the investigated analye during the ashing phase,to increase vaporization of the matrix,and to reduce transport losses was investigated.Optimum analysis results were obtained with PdCl_2 modifier when 500 ng Pd was used for a sample weight of 100 #mu#g Al_2O_3 injected into the ETV. Calibration was perfoemed by standard addition with aqueous solutions of the analytes. The RSDs calculated from triplicate analysis ranged form 5 to 10%. Detection limits between 0.07 #mu#g g~(-1) (Ga) and 1.1 #mu#g g~(-1) (Na) were achieved. The accuracy was proven for the elements Ca,Fe,Ga,Mg,Mn,Na,Ni,and V by analyzing an NIST standard reference Al_2O_3 material (SRM 699) with a middle grain size of 16.4 #mu#m..The analytical method was used for the analysis of Al_2O_3 powder (AKP 30,Sumitomo,Japan) with impurities in the low #mu#g g~(-1) range and a grain size of 1.1 #mu#m. The results obtained for the elements Ca,Fe,Ga,Mg,Mn,Na,Ni,and V were comoparable with those obtained by ICP-MS subsequent to conventional decomposition with hydrochloric acid high pressure.