B-Z Oscillating Chemical Reactions And Their Analytical Applications

In recent years, the nonlinear phenomena have been more and more recognized and the oscillating chemical reactions, as the most important nonlinear phenomenon in chemical systems, have been widely investigated by many scientists as well. And the mechanisms of the classical chemical oscillating systems seemed to get more expressly. Due to some advantages, such as simpleness in set-up, convenience of operation, widely linear range and lower detection limit and so on, many analysts also have paid their attention to analytical applications of chemical oscillating reactions.In this thesis, a S^2- modified B-Z oscillating system has been successfully used to determine some heavy metal ions and through examining the influence of S^2- and benzylpenicillin sodium on B-Z chemical oscillating reaction highly sensitive detection methods of them have been developed.Mechanism of classical B-Z chemical oscillating reaction and corresponding Oregonator mathematical model are introduced in detail and recent advances on study of analytical applications of B-Z oscillations are reviewed.Certain amounts of sulfur ion are introduced into the classical B-Z system to improve oscillating behaviour of the system. And then a new method for determination of some of trace amounts of heavy metal ions such as Ag⁺, Pb²⁺, Hg²⁺, Cd²⁺, Cu²⁺and Bi³⁺ by the S^2- modified B-Z chemical oscillation system is established. And the results have showed that the change in the oscillating period is linearly proportional to the concentration of the cations in a wider concentration range and the method is sensitive, quick and selective. Various influencing factors on the experiments were also examined.A highly sensitive and highly selective method has been described for the determination of trace amounts of cadmium ion in aqueous solutions. The results show that in this S^2- modifyed oscillation system the change in the oscillating period was linearly proportional to the concentration of the cadmium ion in the range from 6.15×10^-10 to 3.88×10^-12 mol·L^-1 with a lower detection limit of 9.2010^-13 mol·L^-1 and many co-existence heavy metal ions do not interfere the measurement of cadmium ion. A new method of determination of S^2- ion in aqueous solution is developed based on the classical Belousov-Zhabotinskii (B-Z) oscillating reaction. After injecting S^2- ion solution into the systems, the oscillating period is disturbed and increase quickly, and the change in the oscillating period was linearly proportional to the concentration of the S^2- ion with a wider range from 7.94×10^-8 to 3.16×10^-5 mol·L^-1. The proposed method hs been used in analysis of a simulative water sample solution and the results are exact and credible.Both the perturbation of Benzylpenicillin Sodium and the effect of the variables on the proposed chemical oscillating system are studied in detail. The results show that the change in the oscillating period was linearly proportional to the concentration of Benzylpenicillin Sodium over the range from 2.47mg/L- 0.0123mg/L. Using the procedure, the content of the antibiotic in a bought production is determined and the result was consistent with that by HLPC.