Simultaneous detection of trace adulterants in food based on multi-molecular infrared (MM-IR) spectroscopy

Simultaneously rapid detection of trace adulterants in the complex systems of food without extraction is considered highly challenging. Herein, a high-throughput and rapid methodology, multi-molecular infrared (MM-IR) spectroscopy was developed for simultaneous detection of multiple trace adulterants in food. Flour was applied to demonstrate the capabilities of MM-IR with spatial resolution, spectral qualitative and quantitative analysis. Signals of 5 trace adulterants (rongalit, potassium bromate, borax, aluminum potassium sulfate and fluorescent brighter) were spatially revealed by IR hyperspectral imaging with group-peak matching, and further unveiled spectrally with second derivative two dimensional correlation infrared (SD-2DCOS IR) spectroscopy for higher resolution. Moreover, quantitative analysis of trace adulterants was conducted with partial least squares (PLS) modeling in ppm level. Composed of the above techniques and a series of resolution enhancement techniques (MW-2DCOS IR, 2T-2DCOS IR, etc.), MM-IR presented significant advantages on simultaneous detection of trace adulterants in food and therefore possessed the potential for food comprehensive analysis.