Effective identification of paints pigments in hit-and-run cases with confocal Raman microscope

Purpose The purpose of this paper is to identify different automotive coatings using Confocal Raman microscope which could hardly be differentiated with Fourier transform infrared microscope (FTIR). Design/methodology/approach Raman spectroscopy was used to provide extra vibration information to infrared spectroscopy. Paints preparation was not necessary, and only 30 s was needed for each sample in an optimised method. Paints were first analysed by FTIR and then compared with Raman microscope. Findings Raman microscope was used to address the lack of ability of FTIR in discriminating four groups of paints in same colours. This study indicated that Raman microscopy is especially effective in sensing pigments and could successfully identify all pigments in the paints. Research limitations/implications The two instruments in combination produce accurate results than when used individually, especially in complex and multi-layered paints analysis. Practical implications The method proved to be fast, accurate and non-destructive, and it could be easily applied to real cases. Originality/value With this method, scientists could discriminate some coating types which were hard to be discriminated by other techniques.