Identification of polymers by libs using methods of correlation and normalized coordinates

Laser-induced breakdown spectroscopy (LIBS) is an elemental analysis technique that is based on the measurement of atomic emissions generated on a sample surface by a laser-induced microplasma. The technique has been applied to the identification of high- and low-density polyethylene (HDPE, LDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), poly-vinyl chloride (PVC), poly(tetrafluoroethene) (PTFE), poly(tetrafluoroethene) with 15% aluminium, nylon, cellulose and rubber. In previous works, we have shown that simple statistical methods, such as linear and rank correlations, and ratios determination can be successfully applied for the instant identification of different kinds of polymers. In this work, the Method of Normalized Coordinates (MNC), a new statistical method, linear and rank correlation have been applied to identify polymers with a very similar chemical composition by LIBS. The probability of a correct identification has been estimated for each statistical method. They provided effective identification and discrimination at a 95% confidence level.