Chromatographic determination of UV absorbers in car paints

Car paints not only must be stable to sunlight effects but also must protect paint sub-layers. For this purpose, the transparent melaminic/acrylic paints of recent formulation contain added stabilisers (UV-As) which are able to absorb UV radiation. The present work presents a chromatographic method that can be easily applied in industrial laboratories for the separation and determination of three hydroxybenzotiazoles, commercially known as Tinuvin 900, Tinuvin 328, and Tinuvin 1130, widely used as UV absorbers. The method, that involves the extraction process from the polymeric matrix and the RP- HPLC determination is validated with respect to a lab prepared model paint and applied to commercial samples of known and unknown composition.