Identification of post-consumer plastics using laser-induced breakdown spectroscopy

We report an accurate recognition of ten different types of postconsumer plastics, including five extensively used basic plastics, by laser-induced breakdown spectroscopy (LIBS). Ratiometric and correlational analysis have been performed for the classification in which C/H ratio yielded partial discrimination while an excellent correlation has been observed between the intensity of the carbon peak with carbon single bonds. Additionally, a 3D correlational approach using the emission intensities of carbon, hydrogen, oxygen and nitrogen lines successfully segregated all the plastics. Finally, we report findings from partial least squares- discriminant analysis (PLS-DA) that demonstrates classification accuracies of over 93 %. We envision that the high classification accuracy is shown here will encourage further validation studies leading to routine application of LIBS for screening and identification of post-consumer plastics.