Determination of calcium, magnesium and aluminium in magmatic rocks after ultrasonic leaching by flame AAS

A method of ultrasonic leaching has been developed for the destructive analysis of magmatic rock $samples^1$. This method was applied to determine three new elements, Ca, Mg and Al, in magmatic rock samples. The accuracy of the ultrasonic leaching method ($C_{ULM}$) was tested using standard reference materials (SRMs) and the recovery ratio as $K_1 = $C_{ULM}/C_{SRM}$ was defined. Another recovery ratio, $K_2$, was also defined from the results of the conventional dissolution method (CDM), that is $K_2$ = $C_{ULM}/C_{CDM}$. The accuracy and precision of the method are comparable with those of conventional methods. The following recovery ratios were obtained for Ca, Mg and Al, respectively. 96% < $K_{1,Ca}$ < 112% and 95% < $K_{2,Ca}$ < 112%, 93% < $K_{1,Mg}$ < 109% and 94% < $K_{2,Mg}$ < 108% and 91% < $K_{1,Al}$ < 102% and 94% < $K_{2,Al}$ < 107%.