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English| Launch：2019-07-26 |
* Introduction
Raman spectroscopy is a method of finger mark identification based on Raman scattering principle. When light interacts with molecules, most photons scatter elastically, only a few photons scatter inelastically, and part of the energy is transferred to molecules, so that the frequency of scattered light shifts (the displacement carries molecular information). Due to the different molecular structure and displacement, the corresponding Raman spectra are also different, so the Raman spectra can be used to detect the presence and relative content of chemical substances in the samples.
Throughout recent food safety incidents, we can easily find that melamine, Sudan red, malachite green and other illegal additives can be said to be the culprit. Therefore, the development of rapid and accurate detection technology for illegal additives has become an urgent task for food safety detection industry. At present, the main detection methods of these common illegal additives include GCMS, HPLC, LC-MS, and so on. Although these methods can be used to detect unknown samples qualitatively and quantitatively, there are obvious shortcomings such as tedious pretreatment process, high detection cost, long inspection cycle, expensive instruments and so on.
Raman spectroscopy, as a fast, non-destructive and safe detection technology, has the characteristics of accuracy, rapidity, good reproducibility, simple sample pretreatment, compactness, portability and wide application. Now it has been used in illegal additives, excessive use of additives (such as synthetic pigments in food), pesticide residues in fruits and vegetables. Adulteration and other tests play a positive role.
* Application
Rapid screening of Sudan red by EVA3000Plus Raman spectrometer
Fig.1 Raman spectra of Sudan I, II and III
As can be seen from Fig. 1, Sudan I, II and III have corresponding characteristic Raman peaks. Sudan I has characteristic Raman peaks at 458, 718, 990, 1091, 1163, 1224, 1335, 1385, 1450, 1492, 1593 cm-1; Sudan II has fewer characteristic Raman peaks, which are 454, 708, 982, 1225, 1378, 1492, 1602 cm-1. The characteristic Raman peaks of III are 456, 716, 981, 1127, 1227, 1383, 1415, 1437, 1492 and 1591 cm-1. The standard samples of Sudan I, II and III can be detected by the Raman spectrometer of marine optics. In addition, combined with relatively simple pretreatment methods (such as organic extraction and purification, some components in the extract can effectively remove the interference of Sudan red Raman signal), EVA3000Plus Raman spectrometer can also be used for the screening of Sudan red in chili sauce, tomato sauce, beverage and other food samples.
