Direct atomic spectrometric analysis by slurry atomisation. Part 6. Simplex optimisation of a direct current plasma for kaolin analysis

Abstract

The simplex optimisation of a three-electrode direct current plasma for the determination of magnesium in aqueous slurries of kaolin is described. The viewing position was the most critical parameter with the optimum position for the Mg II 279.079-nm line being in the boundary of the analytical zone and plasma core. Temperarature measurement suggest that slurry loadings in excess of 12%m/V cool the plasma. Mechanisms for this effect consistent with existing excitation models are suggested. When slurry concentrations are maintained at 10%m/V or below excellent linearity is observed in slurry calibration graphs.