A new method for determining aflatoxins in groundnut and groundnut cake using Fourier transform infrared spectroscopy with attenuated total reflectance

A new analytical method was developed for the determination of aflatoxins i n groundnut and groundnut cakes by Fourier transform infrared (FTIR) spectr oscopy using horizontal attenuated total reflectance technique. Groundnut a nd groundnut cake samples were used in this study. The wavelengths were sel ected for the four types of aflatoxins-B-1, B-2, G(1), and G(2)-and the sta ndards prepared for each by spiking some clean sample with the aflatoxins i n concentrations of 0-1200 parts per billion. A partial least square regres sion was used to derive the calibration models for each toxin. The coeffici ents of determination (R-2) of the calibration model were computed for the FTIR spectroscopy predicted values vs. actual values of aflatoxins in parts per billion. The R-2 was found to be 0.9911, 0.9859, 0.9986, and 0.9789 fo r aflatoxins B-1, B-2, G(1), and G(2), respectively. Standard errors of cal ibration for groundnut samples were found to be 1.80, 2.03, 1.42, and 2.05 for aflatoxins B-1, B-2, G(1), and G(2), respectively. Calibration models w ere validated with an independent set of samples. The R-2 of validation mod els were computed. The SD of the difference for repeatability of the FTIR m ethod was found to be better than that of the chemical method. Based on the results obtained, FTIR spectroscopy can be a useful instrumental method fo r determining aflatoxins in oilseeds and oilseed cakes. With its speed and ease of data manipulation by computer software, it is a possible alternativ e to the standard wet chemical methods for a rapid and accurate routine det ermination of aflatoxin levels in food and feed.