Direct determination of total isothiocyanate content in broccoli using attenuated total reflectance infrared Fourier transform spectroscopy

Abstract The determination of total isothiocyanate content in broccoli is described using attenuated total reflectance Fourier transform infrared spectroscopy (ATR FT-IR) and partial least-squares (PLS) algorithm. The spectral region of 2150–2020 cm −1 was used for the total isothiocyanate quantification. The correlation coefficient was 0.99992, the root-mean-square error of calibration (RMSEC) was 1.74 and the root-mean-square error of prediction (RMSEP) was 2.17. The results were compared with those obtained from an established UV–Vis spectrophotometric method. The two methods were equivalent in reproducibility and accuracy ( F -test, t -test). The proposed ATR FT-IR method is simpler and more rapid than the existing methods and constitutes a useful alternative for the determination of total isothiocyanates in broccoli.