1. INFRARED SPECTRA AND CHEMOMETRICS A POWERFUL TANDEM IN LEATHER INDUSTRIES: DIRECT CHARACTERIZATION OF LEATHER FINISHING T. Canals (a), R. Cantero (a), G. Cepas (a), I. Escuredo (a), H. Iturriaga (b), Ll. Izquierdo (c) and J.R. Riba (a) (a) EUETII, L’Escola d’Adoberia, Universitat Politècnica de Catalunya, Igualada, Barcelona, Spain. (rcantero@euetii.upc.es). (b) Facultat de Ciències, Química Analítica. Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain. (hortensia.iturriaga@uab.es) (c) PielColor S.A., 08291 Ripollet (Barcelona). INTRODUCTION Leather finishing is one of the fundamental stages in the process of transforming hides into final leather. Leathers undergo different types of finishing depending on their characteristics or final destination. Those several coats of chemicals with various properties are applied on tanned leather. Due to the great variety of chemicals used in this operation it is hard to have a simple analytical methodology available that would allow us to identify the type of finishing used once applied on the leather. In this work, we present the use of chemometric treatments of MIR spectra to carry out a general classification according to applied finishing (resins, waxes-oils and degrained) and the type of resin being used (acrylic, polyurethane and butadiene). OBJECTIVE Establish an analytical method to group and classify the type of formulation used in leather finishing in a quick and direct way with the help of infrared spectroscopy and chemometric treatment of spectra. STUDY 1 1 – Finishing leather samples (65): - Degrained (7) - Waxes-oils (11) - Resins (47) 2 – Recording of the samples MIR spectra 3 - Data processing with PCA/CVA 4 - Results CONCLUSIONS In spite of complexity of the final product, the different essays performed indicate that finished leathers are grouped and classified correctly according to the type of resin being used and that the presence of pigment or lacquer has no influence at all on the classification of finished leather. Therefore, the tandem infrared spectra and chemiometric analysis offers great possibilities of implementation in the analysis of leather finishing. APLICATION OF CHEMOMETRIC METHOD EXPERIMENTAL 1 - Instrumentation: FTIR Spectrum One (PerkinElmer) equipped with ATR module (4000-650 cm -1 ). 2 – Recording of MIR spectra. 3 - Data processing with: - Principal Components Analysis, PCA * - Canonical Variates Analysis, CVA * 4- Results presentation: - Two-dimensional graphics. - Distance samples by K-Nearest Neighbour method. * Sofware programs by J.R. Riba. STUDY 2 1 – Finishing leather samples with different types of resins (43): - Acrylic: with pigment (8) / whithout pigment (12) - Polyurethane: with pigment (6) /without pigment (11) - Butadiene: with pigment (2) / without pigment (4) The same group of samples is studied after applying a thin lacquer coat. 2 – Recording of the samples MIR spectra 3 - Data processing with PCA/CVA 4 - Results CALIBRATION (26)PREDICTION (17) Butadiene resins   Acrylic resins   Polyurethane resins   CALIBRATION (55)PREDICTION (10) Resins   Degrained   Waxes-oils  