Detection Of Artificial Sweeteners In Food By Surface Enhanced Raman Scattering

At present,food safety has become a common social problem,and many food safety problems are caused by the illegal addition of various substances,including some food additives.Although some food additives can deliberately improve the appearance of food,improve the taste of food,or play the role of anti-corrosion and quality assurance,excessive intake of some additives may cause certain harm to human health,and long-term intake may even cause body damage.As a common food additive,sweetener can be added to almost all foods.In order to ensure food safety,there are clear regulations on the use of sweeteners in China.The commonly used methods for the detection of sweeteners in food are spectrophotometry,gas chromatography,high performance liquid chromatography,high performance ion chromatography,high performance liquid mass spectrometry,capillary electrophoresis,etc.However,the pretreatment process of these methods is complex,cumbersome and time-consuming,so it is necessary to establish a simple,nondestructive and rapid method for the analysis of sweeteners in food.As a sensitive and high resolution spectroscopy technology,SERS can be used to measure analyte information of samples without adding other reagents or destroying samples.At present,SERS technology is widely used in the fields of physics,chemistry,biology,sensing,detection and recognition.In this paper,the Raman spectral characteristics of three common artificial sweeteners are analyzed,and the possibility of Raman enhancement of these sweeteners by silver nanoparticles is demonstrated.In addition,Polydimethylsiloxane?PDMS?plasma cavity substrate and polyurethane nano silver composite substrate were prepared for SERS technology.The SERS spectra of aspartame added in pure water and sucralose added in white wine were measured and analyzed quantitatively according to the SERS spectra.The specific work is as follows:1.The Raman spectra of several sweetener molecules were calculated by Gaussian 09program,and their main characteristic peaks were assigned,and the possibility of Raman enhancement of these sweeteners by silver nanoparticles was analyzed,which was the basis of SERS detection and quantitative analysis of characteristic peak intensity.2.PDMS plasma cavity substrate and polyurethane nano silver substrate were prepared.In order to improve the enhancement performance of the Raman probe,we compared the experimental results and optimized the preparation conditions of the substrate.3.The spectra of aspartame and sucralose,which are widely used in food,were measured by SERS,and the relationship between the intensity of the main Raman characteristic peaks and the concentration of these substances was analyzed.It can be seen from the experimental data that the intensity of Raman characteristic peak will increase with the concentration of sweetener at first,but with the concentration increasing,the intensity of Raman characteristic peak will slow down,and finally slow down.4.SERS detection based on PDMS plasma cavity with optimized parameters,the equation between the Raman characteristic peak intensity of aspartame added in purified water and the amount of aspartame added was established.The determination coefficient R²of the data was greater than 0.99,so the concentration of aspartame added in purified water by SERS method was realized Detection.5.Using polyurethane nano silver block as SERS substrate,which is simple in preparation process and low in cost but has obvious Raman enhancement result,the trace detection of sucralose added in liquor is realized,and the detection limit is up to 10^-8mol·L^-1.In conclusion,the basis and method of this study can provide the basis for the quantitative detection of sweeteners in beverages.