Detection of trace impurities by time-of-flight mass spectrometry with laser-induced evaporation

A method for the determination of trace impurities of tens of ppm in solid materials is proposed, based on laser-induced evaporation of the substance in a vacuum in the forced congruence mode with simultaneous analysis of the evaporation products using a time-of-flight mass spectrometer. The results of measurements of the relative composition of impurities in $\alpha$-corundum obtained from aluminum hydroxide $(\rm AlOOH)$ powder by high-temperature annealing ($1500$ and $1800^{\circ}$C) are presented. The necessity of comparative analysis is caused by a substantial difference in the measurement results for impurities in the initial material obtained by conventional methods. The reported values of the relative composition of impurities are in a good agreement with the results of inductively coupled plasma mass spectrometry (ICP-MS).