Jimei Song

Determination of Alizarin Red S using a novel B-Z oscillation system catalyzed by a tetraazamacrocyclic complex

A new and convenient method for the determination of Alizarin Red S by the perturbations caused by different amounts of Alizarin Red S on a novel B-Z oscillating system is proposed. This new type Belousov-Zhabotinskii involves a macrocyclic copper(II) complex [CuL](ClO4)2 as catalyst and malic acid as the substrate. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. It is found that the relationship between the change in the oscillation amplitude and the logarithm of the Alizarin Red S concentration in the range of 1.5 × 10−7 to 1 × 10−3 M fits a polynomial model: ΔA = 659 + 184.2 log [Alizarin Red S]+ 12.9 log2 [Alizarin Red S]. The RSD obtained with ten samples is 4.4%. The probable mechanism involving the perturbation of Alizarin Red S on the oscillating chemical system is also discussed.

Identification of Two Aliphatic Position Isomers between α- and β-Ketoglutaric Acid by Using a Briggs–Rauscher Oscillating System

This paper reports a novel method for identification of two aliphatic position isomers between α-ketoglutaric acid (α-KA) and β-ketoglutaric acid (β-KA) by their different perturbation effects on a Briggs-Rauscher oscillating system, in which tetraaza-macrocyclic complex [NiL](ClO4)2 is used as the catalyst. The ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results have shown that addition of α-KA into the system does not affect the oscillating patterns, while the presence of β-KA in a dynamic system influences the oscillatory amplitude. A more interesting feature is that, in the presence of a higher concentration of β-KA, there are damped oscillations after the initial spike, followed by quenching (more exactly: very small oscillations) of the oscillations before the subsequent regeneration of oscillations. A qualitative approach was thus established by employing a Briggs-Rauscher system for identification of these two isomers. The concentrations of these two isomers that can be distinguished lie over the range between 5.0 × 10(-6) and 2.5 × 10(-3) mol/L. A reaction mechanism based on the FCA model has been proposed. An explanation is that β-KA reacts with HOO(•) radicals to form acetone, whereas the α-KA does not.

Kinetic determination of tannic acid using a Belousov-Zhabotinskii oscillating system catalyzed by a macrocyclic complex

Abstract An analytical method for the determination of tannic acid is proposed by the sequential perturbation caused by different amounts of tannic acid on the Belousov-Zhabotinskii oscillating system. The oscillating system is catalyzed by tetraazamacrocyclic complex [CuL](ClO4)2, where L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The method relies on the linear relationship between the changes in the inhibition time and the logarithm of the concentration of tannic acid. The calibration curve obeys a linear equation very well when the concentration of tannic acid is over the range of 6.25 × 10-7 ~ 1.56 × 10- 5 M (n = 16, R = 0.9984). This analytical method, equipped with a simple instrument, provides a new way to accurate determination of tannic acid. Graphical Abstract