HPLC Studies on the Organic Subset of the Oscillatory BZ Reaction. 3. Products of the Ce4+−Bromomalonic Acid Reaction

1998 ◽  
Vol 102 (6) ◽  
pp. 922-927 ◽  
Author(s):  
Julia Oslonovitch ◽  
Horst-Dieter Försterling ◽  
Mária Wittmann ◽  
Zoltán Noszticzius
1994 ◽  
Vol 98 (34) ◽  
pp. 8377-8380 ◽  
Author(s):  
Ying Gao ◽  
Horst-Dieter Foersterling ◽  
Zoltan Noszticzius ◽  
Bernhard Meyer

Author(s):  
Irving R. Epstein ◽  
John A. Pojman

In the previous chapter, we developed a set of conceptual and mathematical tools for analyzing the models and experimental data that form the subject matter of nonlinear chemical dynamics. Here, we describe some of the key items of experimental apparatus used to obtain these data so that the reader can better appreciate the results discussed in the following chapters and can learn how to begin his or her own investigations. The first several sections are devoted to measurements of temporal behavior, with emphasis on the techniques used to monitor reactions in time and on the reactors in which these reactions are studied. The final section focuses on the study of spatial patterns and waves in chemical systems. It is possible, by methods that we shall discuss later, to reconstruct the qualitative dynamics of a system from the measurement of only a single variable. However, the more species whose concentrations can be measured, the easier it is to elucidate a mechanism and the more rigorously that mechanism can be tested. The most impressive study of multiple species in a chemical oscillator was carried out by Vidal et al. (1980), who were able, by a combination of techniques, to monitor the concentrations of Ce4 + , Ce3+ , Br2, Br-, bromomalonic acid, O2, and CO2 in the BZ reaction. In the following sections, we will look at the most widely employed techniques: spectroscopic and potentiometric methods. In principle, and occasionally in practice, essentially any technique that can be used to detect changes in concentration can be utilized to monitor the systems that we are interested in. Approaches that have been employed to date include polarography, high-pressure liquid chromatography, and calorimetry. If there are absorbing species, ultraviolet and/or visible (UV/vis) spectroscopy offers rapid response time and high sensitivity for monitoring concentrations, particularly if the species of interest have spectra with relatively little overlap. Measurements can be made in a cuvette placed in a standard UV/vis spectrophotometer, but this configuration has several limitations.


1980 ◽  
Vol 44 (02) ◽  
pp. 111-114 ◽  
Author(s):  
Hiroshi Takayama ◽  
Minoru Okuma ◽  
Haruto Uchino

SummaryTo develop a simple method for estimation of platelet lipoxygenase (PLO) and cyclo-oxygenase (PCO) pathways, the arachidonic acid (AA) metabolism of human platelet was investigated under various experimental conditions by the use of the thiobarbituric acid (TBA) reaction and a radioisotope technique. A TBA-reactive substance different from malondialdehyde (MDA) via PCO pathway was detected and shown to be derived from the PLO pathway. Since the optimal pH and time course of its formation were different from those of MDA formation via PCO pathway, PLO and PCO pathways were estimated by quantitating the TBA-reactive substances produced by the incubation of AA either with aspirin-treated platelets or with untreated ones, respectively, each under optimal conditions. Normal values expressed in terms of nmol MDA/108 platelets were 1.17±0.34 (M±SD, n = 31) and 0.79±0.15 (n = 31) for PLO and PCO pathways, respectively.


2019 ◽  
Author(s):  
Liman Hou ◽  
Marta Dueñas-Diez ◽  
Rohit Srivastava ◽  
Juan Perez-Mercader

<p></p><p>Belousov-Zhabotinsky (B-Z) reaction driven polymerization-induced self-assembly (PISA), or B-Z PISA, is a novel method for the autonomous one-pot synthesis of polymer vesicles from a macroCTA (macro chain transfer agent) and monomer solution (“soup”) containing the above and the BZ reaction components. In it, the polymerization is driven (and controlled) by periodically generated radicals generated in the oscillations of the B-Z reaction. These are inhibitor/activator radicals for the polymerization. Until now B-Z PISA has only been carried out in batch reactors. In this manuscript we present the results of running the system using a continuously stirred tank reactor (CSTR) configuration which offers some interesting advantages.Indeed, by controlling the CSTR parameters we achieve reproducible and simultaneous control of the PISA process and of the properties of the oscillatory cargo encapsulated in the resulting vesicles. Furthermore, the use of flow chemistry enables a more precise morphology control and chemical cargo tuning. Finally, in the context of biomimetic applications a CSTR operation mimics more closely the open non-equilibrium conditions of living systems and their surrounding environments.</p><p></p>


1983 ◽  
Vol 48 (11) ◽  
pp. 3223-3228 ◽  
Author(s):  
Peter Ševčík ◽  
Ľubica Adamčíková

The kinetic parameters of the reaction steps of the oscillation cycle and the parameters of modified oscillation reactions of the Belousov-Zhabotinskii (BZ) type with oxalic acid, tartaric acid, and hypophosphite ions were compared with predictions of Edelson's analysis based on the mechanism of the classical BZ reaction.


2000 ◽  
Vol 61 (5) ◽  
pp. 5326-5329 ◽  
Author(s):  
Osamu Inomoto ◽  
Koji Abe ◽  
Takashi Amemiya ◽  
Tomohiko Yamaguchi ◽  
Shoichi Kai

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