Multivariate quality control was used in conjunction. with Fourier transform infrared spectroscopy to detect the oxidation process in soybean oils. The multivariate approach was abased on principal component analysis (PCA) to develop two control charts: a T-2 chart using the most significant principal components and a Q chart with the remaining PCs hot used in the first one. From these-two charts it was possible to identify oxidation levels in oil samples which were out of the pattern normally present in edible soybean oils.355729739