A Novel Ni（Ⅳ） Complex –Luminol Chemiluminescence System Coupled With Flowinjection For Determination Of Two β₂-agonists

Ractopamine and Fenoterol are β- stimulant drugs. Ractopamine can be used to help treat congestive heart failure, muscular dystrophy, muscle adding and reduce the build-up of fatty deposits. What’s more, it is beneficial to embryo and neonate’s growing. Fenoterol is a kind of efficient bronchodilators and it is used to treat bronchial asthma and other reversible airway stenosis such as chronic bronchiolitis obliterans or emphysema. However, both of them belong to a kind of clenbuterol used as animal feed additives to help chicken, pigs and cattle add muscle(commonly known as lean meat), reducing their fat. When taken in too much, they can cause live stocks to be poisoned and food remain. People who have taken in animal derived food containing ractopamine and fenoterol for a long time can be poisoned. When the content of ractopamine and fenoterol reaches a certain amount, toxic effect would be caused acute and chronic poisoning, mostly cumulating chronic poisoning. This chronic poisoning possibly causes eaters to have cancer, become abnormal and have a mutation, which is very harmful for people’s health. Therefore, to establish a new easily operated, rapid and sensitive mehod for determination ractopamine and fenoterol’s residues has practical implications for the security detection of animal derived food.In alkaline medium, Ni(IV) complex and luminol generates steady CL(chemiluminescence) signals. Ractopamine and fenoterol can observably increase the CL intensity, and show a good linear relation within a certain range. This experiment is aimed to establish a new method to detect ractopamine and fenoterol by Ni(IV)complex-Luminol CL system coupled with flow injection technique. PART 1 Determination for Ractopamine based on Ni(IV)-Luminol CL system Coupled with FlowinjectionObjective: To establish a flow injection-Ni(IV)-Luminol CL new system and determination ractopamine in animal feed sold in the market.Methods: In alkaline condition, Ni(IV) complex-Luminol generates steady chemiluminescence signals. Observably, ractopamine can enhance the CL intensity. Moreover, the relative intensities with the concentration of the sample show a fine linear relation within limits. In the optimum detection condition, the standard curve is drawed and the content of the sample is detected through optimized a series of determination conditions containing Luminol and Ni(IV) solution concentration and alkalinity. A new method in determining ractopamine with flowinjection-Ni(IV)-Luminol CL system is established.Results: In the optimized experimental condition, the detection limit of ractopamine is 1.0×10-10 mol/L, showing a good linear relation range from 1.0×10-8 ~ 1.0×10-6 mol/L. The RSD of 1.0×10-7mol/L ractopamine is 1.65% by 13 times parallel determination. Under optimum conditions, the proposed method has been applied to the analysis of swine feed samples with satisfactory results.Conclusion: The flowinjection CL analytical method for determination ractopamine is simple, sensitive, rapid, accurate and reliable by adopting Ni(IV)-Luminol CL new system. The content of ractopamine in animal feed sold in the market isdetermined and the result is satisfaction. PART 2 Determination for Fenoterol with flow injection- Ni(IV)-Luminol chemiluminescence new systemObjective: To establish a flowinjection-Ni(IV)-Luminol CL system for determination fenoterol in animal feed.Methods: In alkaline condition, Ni(IV)complex-Luminol generates steady CL signals. Observably, fenoterol can enhance the CL intensity, and the CL relative intensity with fenoterol concentration have a good linear relation within limits. In the optimum detection condition, the standard curve of fenoterol is drawed and the content of the sample is determined through optimized a series of determination conditions containing Luminol and Ni(IV) solution concentrations and alkalinity. A new method for determination fenoterol by Ni(IV)-Luminol CL system coupled with flow injection is established.Results: In the optimized experimental condition, the detection limit of fenoterol is 1.0×10-11 mol/L, showing a good linear relation range from 1.0×10-9 mol/L ~ 1.0×10-7 mol/L. The RSD of 3×10-8 mol/L fenoterol is 0.71% by 13 times paralleldetermination. Under optimum conditions, the proposed method has been applied to the analysis of swine feed samples with satisfactory results.Conclusion: The proposed CL method for determination fenoterol is simple, sensitive, rapid, accurate and reliable based on Ni(IV)-Luminol CL new system. The content of fenoterol in animal feed sold in the market is determined and the result is satisfaction. Under optimum conditions, the proposed method has been applied to the analysis of swine feed samples with satisfactory results. PART 3 Proposed the Chemiluminescence reaction mechanism of ractopamine and fenoterolBoth ractopamine and fenoterol are β-stimulant drugs and their chemical structures are similar. In the determination of Ni(IV)-Luminol CL system, two drugs both enhance the CL intensity of the system, so it is supposed that their reaction mechanisms should also be similar. The UV visible spectra, fluorescence spectra and CL spectra of Ni(IV)-luminol ractopamine/fenoterol CL system are studied by scanning or determination. Through the analysis of the spectra, the possible CL reaction mechanism of this system is inferred:The reaction between Ni(IV), Luminol and ractopamine /fenoterol are free radical reactions. The reactions of ractopamine /fenoterol with Ni(IV) is much faster than that of Luminol with Ni(IV). And in the reaction process, some free radicals generated by ractopamine or fenoterol partially transfer to luminol, so that the luminol free radicals increased. Thereby the luminescence species of luminol are increased, so that the CL intensity of the system enhanced.