Determination of the major elements in homogeneous and heterogeneous samples by tandem laser-induced breakdown spectroscopy-partial least square regression

The tandem laser-induced breakdown spectroscopy-partial least square regression (LIBS-PLS) was applied for the analysis of both, a smelting product from a noble metal ore (as example of a homogeneous sample) and a calcareous rock from a Maya building (as a heterogeneous sample). The method was designed for the analysis of both samples without perceptible deterioration of the pieces, by monitoring the emission lines of the major elements present in each sample while subjecting the pieces to a number of laser shots. The results obtained, as well as the precision provided by the LIBS-PLS method, were statistically compared with those obtained by graphite furnace-atomic absorption spectroscopy (for Ag and Cu) and flame atomic emission spectroscopy (for Ca), showing good agreement between methods.