| Sunset yellow is a synthetic azo pigment and a food additive approved by China. It hasmany advantages compared with natural,such as bright color,tinting strength,good stablibiltyand low price.Recently,it has been widely used as additives in the food industry,such as fruitand vegetable drinks,canned food and candy.However,sunset yellow can be pathogenic. It cancause allergies,diarrhea,migraine,asthma if it is excessibely consumed,and can also damagekidney,liver and nervous system.Therefore,it is quite important and worthwhile to developesay and reliable method for detection of sunset yellow in the food products.This paper mainly carried out the following two aspects:1. A molecular imprinted film of sunset yellow with specific identification hole has beendeveloped by molecularly imprinting technology.The sensitive film was prepared by cyclicvoltammetry method on graphite electrode using o-aminophenol as functional monomer,sunset yellow as template which removed by electrochemical method. The preparationconditions were discussed in detail.The experimental results showed that the bestpolymerization conditions are:the upper scanning potential of cyclic voltammertry is1.50,supporting electrolyte is perchloric acid, the concentration of o-aminophenol is0.0135mol/L, the concentration of sunset yellow is2.50×10-3mol/L,the scan weeks are50.Comparison of molecular imprinted modified electrode and non-imprinted molecularmodified eledtrode on the adsorption characteristics of sunset yellow. The experimentalresults indicated that the molecular imprinted modified electrode had a effect of the specialadsorption to sunset yellow.The polymer films were investigated by scanning electronmicroscopy, Uv-vis absorption spectrometry and electrochemical method.2. The dectection conditions of sunset yellow by molecular imprinted modified electrodepr were discussed in detail. The experimental results indicated that the best detectionconditions are: the supporting electrolyte is perchloric acid,adsorption time is30min,potential range is from-1.00to1.50,pulse amplitude is0.04V,pulse interval is3.0s. Thelinear relation between peak current and concentration of sunset yellow were good in therange from1.00×10-6to2.00×10-4mol/L with a detection limit of2.00×10-7mol/L at potentialof0.84V.The imprinted electrode has been applied to determination of sunset yellow.Themolecular imprinted film can be exploited for the separative analysis of sunset yellow with the similarity structural lemon yellow. The reaction mechanism in polymerization depositionof o-aminophenol on graphite electrode and sunset yellow on imprinted electrode are simplediscussion. The structural of poly o-aminophenol in different potentials and the electron andproton transfer number of sunset yellow are speculated. |
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