Study On The Determination Of Trace Elements In Food By Catalytic Kinetic

With the development of economy and standard of living,people has a higher expect for Food Quality Security. the pollution of crop domestic,animals meat,aquatic products in China at present and the contamination of food in yield,preparation,transportation,storage, sale links badly jeopardizes the health of the consumer. The contamination of microelement in food is one of the most severe pollution. Contamination of food posing potential danger to human health has become a serious food safety problem. The injurant analysis in foodstuff is one important part of analysis in Food.The injurant content in foodstuff was less. With the development of the Modernization Production and appearance of large batch of samples, higher request to sensitivity, accuracy, speediness of analysis method. Catalytic kinetics analysis method is of high sensitivity as well as selectivity .The method is simple and does not require costly determination apparatus. The method applies to ordinary quantity, also micro and trace component. It is very suitable for determination of micro component in foodstuff., Catalytic analysis method , as a kind of accurate,convenient analysis method, will enjoy wide application prospects in the middle and small food enterprises,the Grass-roots epidemic prevention and commodity inspection department,medical and health sector . The review discusses general aspects of development in the kinetic determination of microelement in food and food additive. Some new catalytic kinetic methods were also discussed. This result was successfully applied to determination of microelement in food. The concrete jobs are as follows:一,Application of catalytic analysis in food analysisBasic mechanism of catalytic kinetic methods is: there is a certain relation between velocity of chemical reaction, which is accelerated by homogeneous catalyst ,and density of the catalyst (or density activator,inhibitor,Resistance- Relieving Agent), The method can be applied to the determination of these substances. Catalytic method is widely used in foodstuff analysis ,because the method is rather simple,rapid and high sensitivity and good accuracy. This paper summarizes the advances in study on microelement in food and food additive in recent years, and the research items are put forward.二,Determination of trace iodine in vegetable by catalytic spectrophotometryIodine , as the main material of thyroxine synthesis , has important physiological function. Iodine is one of the necessary factors for growth and development of brain, iodine-deficient in anatomy will be able to cause a series of iodine deficiency(IDD). Iodine-deficient in growing period of fetus could cause brain maldelelopment, Iodine-deficient in adult could cause goiter. Intaking appropriate amount iodine is of a great value to maintain human heath. The rich iodine vegetable is good for keeping supplementing iodine in human body. A new catalytic-kinetic spectrophotometric method has been established for determination micro amounts of iodine in vegetable ,which is based on a remarkable catalytic effect of iodide on oxidation of butyl rodamin B by sodium periodate in phosphoric acid medium. Under specific condition of experiment ,the relationship between catalytic reaction velocity and I- concentration will coincidence with linear relation. Hereby , The determination of micro iodine by catalytic kinetic spectrophotometry has been established.三,Study on determination of Trace iodine by catalytic potentiometric methodIodine is one of the essential microelement of human body, Iodine amount in water can comprehensively reflect basic iodine nutrient level of an area. So, Study on the determination of water iodine has very important meaning. A new catalytic potentiometric method for determining micro amounts of iodide is described in the paper .It is based on the catalytic effect of iodide on the oxidation of methyl violet by sodium periodate. Methyl violet electrode made by ourselves has been used for indicating the change of the concentration of methyl violet in the reaction system. This method is easy in operation and convenient in temperature Control. The present method has been applied to the determination of iodine in natural water and drinking water , The average recovery of samples is 98.9% and 99.9%,the average recovery of sample is 1.98% and 1.58%.四,Study on determination of trace copper in oyster by catalytic potential titrationWith the progress of industry and agriculture and research on the exploitation of marine resources, pollution on the sea also emerge out more frequently. These results has made fish and shrimp, which would have provide edible abundance protein , become vector in enriched poisors. In particular bivalves living in offshore bottom such as clam, oyster etc, their enrichment ability to Cu could help to change nontoxic copper to poisonous copper and then enter food and affect human health. A method of catalytic potential titration for the determination of copper (Ⅱ) in the oyster samples by using a crystal violet ion selective electrode as indicator electrode made by ourselves was proposed. It was based on the catalytic effect of manganese (Ⅱ) on the oxidation of crystal violet (CV) by sodium periodate under the presence of nitrilotriacetic acid(NTA). the method needs no complex separation to sample and has high sensitivity,selectivity,high degree of accuracy and excellent reproducibility. It has been applied to the determination of copper in the oyster and the results obtained by this method is agreed with those achieved by atomic absorption spectrometry, the average recovery of sample is 98.72%,and the relative standard deviation is 0.94%.五,Study on determination of trace copper in powder by catalytic titrationIn powder Blasting, oxidants often be used to restrain temperature in beacon combustion in order to control explosive velocity and performance, The common oxidants include copper oxide, iron oxide etc. A method of catalytic potential titration for the determination of copper(Ⅱ) in the powder samples is proposed by using a crystal violet ion selective electrode as indicator electrode made by ourselves It is based on the catalytic effect of manganese(Ⅱ) on the oxidation of crystal violet(CV) by sodium periodate under the presence of nitrilotriacetic acid(NTA). The method is proved to be fast and clear end point, It has been applied to the determination of copper in the powder sample and the results obtained by this method is agreed with those achieved by atomic absorption spectrometry, the average recovery of sample is 98.17%,and the relative standard deviation is 1.02.%.六,Study on cefradine determination by the Resonance Rayleigh Scattering AnalysisCephalosporin is wild-spectrum antibiotic ,which is found after Penicillin. Cefradine is the first generation Cephalosporin. It has a puissant bactericidal activity as well as low price. At present ,Cefradine is widely applied in Clinical application.The paper undertake the research of the effect of Some Surfactants(sodium laurylsulfonate,sodium dodecylsulfate,Cetyltrimethyl ammonium Bromide,Cetyl Pyridine Chloride,β-Cyclodextrin )values on the strength of cefradine resonance rayleigh scattering. Intensity (I). The experimental result indicate that: Anion surface active agent, sodium lauryl sulfonate and sodium dodecyl sulfate can obviously increase I, Among them, the sodium lauryl sulfonate has the most significant influence. Their maximum scattering peaks are at 497 nm. This determination method is high sensitivity and good reproducibility, It has been applied to the determination of Cefradine Capsules, the average recovery of sample is 97.7%,and the relative standard deviation is 0.7%～1.3%.