Oscillating Chemical Reactions And Applications For Pharmaceutical Analysis

The subject of "nonlinear dynamics" and the phenomenon of oscillating chemical reaction, in particular, have become of great interest across of wide range of scientific research in recent years. Oscillating chemical reactions exhibit exotic behavior and unusual mechanisms. Consequently, they have been considered a useful tool for the determination of trace amounts of chemical compounds. This work develops new methods using oscillating chemical reaction for quantitative analytical determinations of barbituric acid, ninhydrin, and heroin for the first time; the accuracy and selectivity of these methods are well pleasing. The main content consists of four parts:Part I. Oscillating chemical reactions and applications for pharmaceuticalanalysisIn this part, we describe the basic concepts of oscillating chemical reactions and FKN mechanism, studies some basic thermodynamic theory related, and gives the conditions of occurring oscillating chemical reactions. Some oscillating chemical reactions that were used in analytical determinations, especially B-Z chemical oscillation, are reported in details. The research progress in applications for pharmaceutical analysis from 1978 to 2003 is discussed systematically through representative examples.Part II. Effect of barbituric acid on the B-Z the oscillating chemicalreaction and its analytical applicationThe effect of barbituric acid on the B-Z oscillating chemical reaction was studied. Results show that the adding of heroin can perturb both the oscillating period and amplitude, the changes of the oscillating period or the amplitude are linearly proportional to the concentration of barbituric acid, which over the range of 6.4×10-7-3.1×10-3 mol/L, and the related coefficient to be 0.9921 and 0.9954, respectively. The possible reaction mechanism has been explained using the FKN mode.Part III. Effect of ninhydrin on the B-Z oscillating reactionThe effect of ninhydrin on the B-Z oscillating chemical reaction was studied. The dependence of the period and the amplitude change on the injected concentration was reported. Results show that the change of the first oscillation period is linearly proportional to the concentration of ninhydrin, which over the range of 6.9×10-7 ~ 4.2×10-2mol/L, and the related coefficient is 0.9977. The possible reaction mechanism has been studied as well as Field-K6r6s-Noyes (FKN) mechanism.Part IV . Determination of heroin using H2O2-CuSO4-KSCN oscillating chemical reaction by the analyze pulse perturbation technique (APP)A new analytical method for the determination of heroin by the sequential perturbation caused by different amounts of heroin on the chemical oscillating system involving the Cu (Il)-catalyzed reaction between hydrogen peroxide and sodium thioyanate in an alkaline medium with the aid of continuous-flow stirred tank reactor (CSTR) is proposed. The method relies on the linear relationship between the changes in the oscillation period of the chemical system and the concentration of heroin, with a detecting limit of 1.2×10-6M. The calibration curve fits a linear equation very well when the concentration of heroin over the range 6.0×10~6 to 1.2×10-4 M (r=0.9971). Influence of temperature, injection points, flow rate and reaction variables are investigated and the possible mechanism of the action of heroin in the chemical oscillating system is discussed. .