Investigations on the use of chemical modifiers for the direct determination of trace impurities in Al2O3 ceramic powders by slurry electrothermal evaporation coupled with inductively-coupled plasma mass spectrometry (ETV–ICP–MS)

Abstract

The direct determination of trace impurities in Al₂O₃ 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) IrCl₃, Pd(NO₃)₂, and PdCl₂ for the determination of Ca, Fe, Ga, Mg, Mn, Na, Ni, and V in Al₂O₃ powders was studied. Their role, which in ETV–ICP–MS and ETV– ICP–OES is to stabilize the investigated analyte during the ashing phase, to increase vaporization of the matrix, and to reduce transport losses was investigated.

Optimum analysis results were obtained with PdCl₂ modifier when 500 ng Pd was used for a sample weight of 100 μg Al₂O₃ injected into the ETV. Calibration was performed 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 μg g^–1 (Ga) and 1.1 μg 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 Al₂O₃ material (SRM 699) with a middle grain size of 16.4 μm. The analytical method was used for the analysis of Al₂O₃ powder (AKP 30, Sumitomo, Japan) with impurities in the low μg g^–1 range and a middle grain size of 1.1 μm. The results obtained for the elements Ca, Fe, Ga, Mg, Mn, Na, Ni, and V were comparable with those obtained by ICP–MS subsequent to conventional decomposition with hydrochloric acid at high pressure.