Raman spectroscopic strategy for the discrimination of recycled polyethylene terephthalate in water bottles

Abstract

A reliable and quick strategy for the discrimination between recycled and virgin polyethylene terephthalate water bottles was developed by applying Raman spectroscopy combined with chemometrics. Chemometric models were created by orthogonal partial least square discriminate analysis (OPLS-DA) using the Raman spectra dataset in the range of 600–1800 cm−1. The Pareto scale model allowed the classification of virgin and recycled terephthalate of polyethylene (PET) samples with a percentage of success of about 95%. In addition, PLS regression was carried out to determine the level of recycled material in the PET water bottles with a good fit (R2 = 0.8920). This analytical approach shows a quick, accurate, and robust way to detect and quantify the adulteration of plastic bottles with recycled plastic materials to avoid fraud in the recycling plastic area.