DETERMINATION OF PEROXIDE VALUES OF EDIBLE OILS BY FOURIER TRANSFORMATION INFRARED SPECTROSCOPY

A Fouriertransform infrared (FTIR) spectrometerquantitativelbased on theprincipleof reflection-absorption was developed to determine the FTIR spectra of edible oils by replacing the sample cup in diffuse reflectance accessory with polished cylinder in the present study.Triphenyl phosphorus oxide was produced by the reaction of peroxide in oils and triphenylphosphine,which were quantitatively determined by FTIR with nitrobenzene as internal standard.The quantitative relationship between peroxide value (Peroxide Value,POV) and FTIR spectral data of edible oils was established by using the ratio of peak height (r) of absorption peak at 542 cm^-1produced by triphenyl phosphorus and 1 531 cm^-1by nitrobenzene,and 9 species (30 samples) of edible oils were determined.The results showed a good linear relationship between POVs and parameter r existed with the equation of POV=14.84×r/m-2.76(m,the mass of the oil sample) and correlation coefficient of 0.998 9.Moreover,the established infrared spectroscopy (POV_IR) method had a good correlation with the national standard method (POV_GB),and the equation was POV_IR=0.944 5×POV_GB-1.00 with the correlation coefficient of 0.998 6,indicating that the established FTIR method could be used to determine POVs of edible oils rapidly and accurately.