Abstract: In the paper, the content of acrylonitrile in SAN was determined by Fourier transform infrared spectrometry (FTIR). By means of the acrylonitrile's characteristic peak at 2237 cm-1 and styrene's characteristic peak at 700 cm-1, the calibrated curve for determining the acrylonitrile content in SAN by FTIR spectrometry was established and its veracity and precision were evaluated. Results showed that its maximum relative error was 2.8 % , the relative standard deviation was 2.48 % when determining the same sample. The method had good veracity and precision.

Key words: Fourier transform infrared spectrometry, acrylonitrile-styrene copolymer, content