Surface-enhanced Raman Scattering (SERS) Detection Of Chrysoidine With Monolithic Column

Unscrupulous traders use Chrysoidine to improve the appearance of food, causing greatharm to human health. Due to the complexity, quickly and widly affection of food, we need afast, accurate universal method to rapid detect Chrysoidine. Surface-enhanced Ramanscattering (SERS) has high sensitivity and high resolution. It is very convenient and accuratefor in situ Chrysoidine detection in many kinds of food. Because of the rich pore structure andrough surface, monolithic column is potential to be a new SERS enhance substrate. Purposeof this paper is to establish a new SERS detection technology with monolithic column todetect the adding of Chrysoidine in food, and in situ detect its adding in drinks.Firstly, this paper optimized monolithic column to get the strongest SERS signal. GMA:EDMA: cyclohexanol: dodecanol=20:20:54:6, react for24h in65℃water bath. Usingscanning electron microscope (SEM) to describe the SERS active site of monolithic column;Secondly, this paper established Chrysoidine SERS detection method with monolithiccolumn. Mixed1:1.5volume of gold colloids and sample, adjusted pH value to9.15, detectedSERS signal within20s~30s on columnar monolithic. This condition could barely not getsignals of Lemon yellow, Sunset yellow, Ponceau4R, Allurared, Amaranth, Erythrosine andBrilliant Blue. Theoretical and experimental Raman spectra of Chrysoidine are compared toget qualitative characteristic peaks. The SERS detection limit of Chrysoidine with monolithiccolumn is0.1μg/mL, while it can only be detected in1μg/mL with gold colloids;Thirdly, this paper established Chrysoidine SERS detection method with monolithiccolumn powder. Mixed1:1.5volume of gold colloids and sample, adjusted pH value to7.74,detected Chrysoidine SERS signal in50μL solution on0.010g monolithic column powderwithin15s~25s. The SERS detection limit of Chrysoidine with monolithic column powderis0.25μg/mL. The stability of this method is not good as SERS detect with monolithiccolumn;Forthly, this paper used yellow (containing equal volume of Chrysoidine, Lemon yellow,sunset yellow), red (containing equal volume of Ponceau4R, Allurared, Amaranth andErythrosine) and blue (Brilliant Blue) color to make out color of representative orange foodextracts. Then SERS method with monolithic column, SERS method with gold colloids, andhigh performance liquid chromatography (HPLC) were used to detect Chrysoidine in foodextracts and spiked food extracts. Experimental results confirmed that Chrysoidine in allspiked food samples can be detected and peak shifts at994cm-1,1138cm-1,1171cm-1,1298cm-1are very stable and recognizable. Traditional SERS method with gold colloids coulddetect only a few spiked samples, and the intensity of the SERS signal was weaker than thosedetected by SERS method with monolithic column;Finally, Chrysoidine in spiked brown, orange, purple and green drinks were in situdetected by SERS method with monolithic column. Chrysoidine concentration was3.81μg/mL,0.78μg/mL,2.58μg/mL,1.64μg/mL, respectively. The SERS signals of Chrysoidineare all very clear. It showed that this SERS method with monolithic column can be used insitu detection of food, avoiding food coloring extraction loss and making the detection step simply. SERS method with monolithic column is expected to be applied for rapid detecting ofChrysoidine in a large number of food samples.