Two-trace two-dimensional correlation spectroscopy (2T2D-COS) approach to analyze Fourier transform infrared (FTIR) spectroscopic data of melamine adulterated milk powder: A quantitative approach.

Due to its importance and being widely traded food commodities, milk powder is considered the target for adulteration. In the present study, a practical, reagent-free and rapid method to identify any variation in the standard composition of milk powder, and extract useful information with respect to adulteration is proposed. Fourier Transform Infrared spectroscopy (FTIR) combined with two-trace two-dimensional correlation spectroscopy (2T2D-COS) was explored not only as a high sensitive method but also as a quantitative routine. With the help of 2T2D-COS-FTIR spectroscopy, melamine was determined in milk powder with superior detection level over conventional second derivative FTIR method. It was interesting to observe that the asynchronous correlation intensities of the cross peak at (814, 1741) cm-1 increased linearly with the difference in concentration of melamine in the two analysed spectra. A calibration curve was established and the concentration of melamine was determined with a limit of detection (LOD) value of 0.46 ppm. The present study represents one method to improve the robustness of the models to make FTIR a more reliable tool for practical applications in the food industry.