Determination Of Three Food Additives Based On The Fenton Reaction And Resonance Reyleigh Scattering Spectrum

Benzoic acid (BA) is commonly used as a food additive. Due to foodpreservation and antisepsis effect having illegal exceed the standard, adding the BAoccurred from time to time. Excessive consumption of BA,it affects human health,may cause cancer.The health detection content of BA is one of the important contentsof food safety evaluation, enhancement of BA health inspection is necessary. Dibutylphthalate (DBP) is a kind of plastic plasticizer, is a kind of important environmentalhormone substance; DBP has be classified as environmental priority control pollutantby China and the United States Environmental Protection Agency (EPA).Melamine (MM) are usually used in the production of melamine/formaldehyderesin.In the human body, the MM is easy to form insoluble salts crystallization, leadto urinary system stones, bladder epithelial hyperplasia, serious harm to human health.DBP and MM are important industrial raw materials, food additives is disabled. Inrecent years, DBP and MM have been illegally used as food additives, led to foodsafety emergencies, has aroused strong repercussions as a result of plasticizers onsome food products with special functions and Join MM to be false dairy productsimprove the protein content. To study new detection methods of the three kinds offood additive substance has important hygienic significance.In this paper, to establish three novel detection methods on fluorescence spectradetection or Resonance Rayleigh scattering spectral based on the Fenton response andResonance Rayleigh scattering spectra, for large area investigation and determinationof the food additive materials(BA, DBP and MM) provides practical new methods.In the second chapter, to establish benzoic acid fluorescence spectrum health detection method based on the Fenton reaction.In pH=7.6near neutral environment,using EDTA-Fe2+/H2O2for the Fenton reagent, benzoic acid formed fluorescentsubstance hydroxyl benzoic acid after it capture·OH radicals from the Fenton reaction.The fluorescence intensities of the hydroxylbenzoic were measured at λex=303nm，λem=414nm. The concentration of the benzoic acid in the food samples was determinedaccording the standard curve. The relatively standard deviations were0.40%~1.40%when the concentrations of the benzoic acid solution were7.0×10-5,1.5×10-4and5.0×10-4mol/L respectively. The standard deviation and the relatively standarddeviations was0.035and3.30%respectively. The calibration graph was linear forthe benzoic acid concentrations of3.53×10-7~9.0×10-4mol/L. The linear recursiveequation was F=98.76c－4.12，（c,×10-4mol/L），r=0.9992. And a detection limit of1.06×10-7mol/L was obtained. The recoveries were within the range of96.50%~102.50%, RSD=2.66%for the fruit juice sample. The method characteristics weresensitive, simple and accurate. And it has been applied to determination benzoic acidin the fruit juice sample with satisfactory results.In the third chapter, new indirect fluorescence spectrumtry determination methodof DBP has been developed.The Fenton reaction generated hydroxyl radicals·OH.The hydrolysis of DBP into adjacent benzene two formic acid sodium. Both reacted toform fluorescent substances hydroxyl adjacent benzene two formic acid sodium. Inthe optimal reaction conditions, in2.8×10-7~2.3×10-4mol/L range, the fluorescenceintensity had good linear relationship with product concentration and, the regressionequation: ΔF=18.47c-11.338(c,10-5mol/L), r=0.9970; the detection limit of8.4×10-8mol/L, the relative standard deviation of1.4%to2.6%; sample recoveries96.73%to105.68%. It was Accuracy and sensitivity.In the fourth chapter, A novel method was established for the determination ofmelamine with barbital by resonance rayleigh scattering (RRS). In the B-R buffersolution (pH=5.5), the melamine reacted with barbital to form large molecules bynon-covalently bound in the THF medium. And there was a strong RRS at the296nm.The intensity of scattering value (ΔI) was applied to determinate of melamine in dairy products. Under optimal conditions, the ΔI value was linear to the concentration ofmelamine in the range of3.03×10-8～1.60×10-7mol/L.And the linear regressionequation wasΔI=1.59c+9.70(c,10-9mol/L), correlation coefficient r=0.9991, thedetection limit was9.1×10-9mol/L.When c=4.0×10-8,8.0×10-8,1.2×10-7mol/L ofmelamine the relative standard deviations were4.54%,3.31%,4.61%（n=11）respectively, the recovery were95.0%~97.5%.The method was more sensitive,simple, the determination of melamine in food with satisfactory results.