Calibration strategies for determination of Pb content in recycled polypropylene from car batteries using laser-induced breakdown spectroscopy (LIBS)

Abstract

This study is dedicated to the evaluation of different calibration strategies applied to solid sample analysis by laser-induced breakdown spectroscopy (LIBS). The calibration strategies evaluated were partial least squares (PLS), principal component regression (PCR) and two-point calibration transfer (TP CT). The proposed calibration strategies were used for determination of lead (Pb) in recycled polypropylene from car batteries. The %trueness values were calculated comparing the predicted concentrations for PLS, PCR and TP CT and the reference concentrations obtained by inductively coupled plasma optical emission spectrometry (ICP OES). For PLS, the trueness value ranged from 74 to 139%, for PCR ranged from 74 to 123% and for TP CT ranged from 100 to 127%, showing in general the good predictive capacity of the proposed strategies. The relative standard deviation (%RSD) values ranged from 3 to 37% (PLS), from 5 to 30% (PCR) and from 6 to 21% (TP CT). In general, the values of % trueness and %RSD for TP CT strategy presented better results. The calibration strategies proposed in this study is highly compatible with LIBS, and it may contribute to minimizing matrix effects in direct solid analysis in complex samples as polymers.