International Journal of Electrochemical Science
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2023
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IF 1.5
Saif Ullah,Gang Hu,Mati Ur Rahman,Asif Hayat,Ata Ur Rehman,Ijaz Ullah,Akhlaq Ahmad,Waqar Uddin,Wen Ma,Zhaohui Fang,Muhammad Yasir Nawabi,Rooh Ullah,Jimei Song
The macrocyclic complex catalyzed Briggs-Rauscher (BR) oscillator was used to determine the antioxidants activity of natural polyphenolic compounds (tannic acid, chlorogenic acid, and luteolin) in this paper. The complex Ni catalyst is donated by NiL(ClO4)2 where the ligand L in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The overall reaction pH was maintained at 2, which is similar to the pH of the human stomach. Experimental results have shown that as per addition of the above antioxidants into the BR system, the temporarily cessation of oscillation was noticed and inhibition time linearly depends on the concentration of antioxidants added. The evaluation of natural polyphenolic compound, antioxidants activity was tested successfully. The three natural polyphenolic compounds tested are tannic acid, chlorogenic acid, and luteolin. In these three natural compounds, the chlorogenic acid was found the most proficient antioxidant. The perturbation mechanism involving HOO● radical based on FCA model was suggested.
研究领域:
化学动力学
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生物化学
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产品关联
DOI
高影响因子
FOOD CHEMISTRY
·
2015
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IF 3.391
Mengshuo Li,Gang Hu,Yangyang Chen
This paper reports a method for evaluating antioxidant capacity based on the inhibitory effects of a macrocyclic Ni(II) complex-catalysed Briggs–Rauscher reaction. The macrocyclic Ni(II) complex NiL(ClO 4 ) 2 , in which L is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene, is a porphyrin-like compound, the structure of which can be found in certain enzymes. The experiments indicated that three natural compounds could temporarily quench the oscillations for a period of time prior to regeneration of oscillations. The inhibition time was related to the compound type and concentration; thus, procedures for evaluating the antioxidant activities of polyphenolic compounds were successfully established. Three polyphenolic compounds were tested to evaluate their antioxidant activities: protocatechuic acid, rutin hydrate and procyanidin. Of these three naturally occurring compounds, procyanidin was found to be the most efficient antioxidant. We have also discussed the reaction of the antioxidant with the hydroperoxyl radical (HOO ) present in the oscillating system.
研究领域:
生物化学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
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2016
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IF 4.803
Juan Chen,Lin Hu,Gang Hu,Yu Zhang,Yuanyuan Hu,Jimei Song
In the analytical field, previous applications of chemical oscillation focused on quantitative analysis. We report in this paper a novel qualitative method electrochemically distinguishing two positional isomers by utilizing their perturbation effects on a catalyzed Briggs–Rauscher (BR) oscillation. The catalyst in the system is a macrocyclic nickel (II) complex NiL(ClO 4 ) 2 , where the ligand L in the complex is 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results indicated that addition of cyclohexane-1,3-dione (1,3-CHD) or 1,4-cyclohexanedione (1,4-CHD) could affect the profiles of potentiometric oscillations, but their changes in the profiles are greatly different. When 1,3-CHD was injected into the oscillating system, there was an initial spiking of the oscillations, accompanying by quenching of oscillations before the regeneration of oscillations. While 1,4-CHD was injected into the dynamic mixture, the oscillatory system responded to the perturbation with only slight decrease followed by a sharp increase in the potential, before it resumed to its normal oscillation state. The perturbation of 1,3-CHD involves inhibition time, whereas the perturbation of 1,4-CHD does not. Hence these two positional isomers could be distinguished by using their different perturbation effects on a BR dynamic system in the range of 9.0 × 10 −4 to 8.0 × 10 −3 M. Our assumption is that, perturbation of 1,3-CHD on the oscillating system involves a radical oxidization process to produce carboxylic acid, whereas perturbation of 1,4-CHD assumes idiodation and elimination steps to form 1,4-benzoquinone. Such different perturbation mechanisms are responsible for the difference in potentiometric oscillation profiles change. This hypothesis was confirmed by products analysis by FTIR and UV spectra.
研究领域:
分析化学
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物理化学
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产品关联
DOI
高影响因子
JOURNAL OF THE CHINESE CHEMICAL SOCIETY
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2016
·Vol. 63
·期 7
·572-579
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IF 0.879
Juanjuan Hu,Gang Hu,Jimei Song,Zhaohui Fang,Xiaofeng Shen,Lin Hu
A novel analytical approach for quantitative measurement of butylated hydroxyanisole (BHA) is dis- cussed in this paper. Such a method depends on the inhibitory effect of BHA on a Briggs-Rauscher (B-R) oscillating reaction. Unlike the classical B-R system which involves Mn 2+ as the catalyst, such a B-R sys- tem is catalyzed by a macrocyclic nickel (II) complex [NiL](ClO 4 ) 2 , where L in the complex is an unsatu- rated ligand 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. By perturbation of BHA on the system, the oscillation was inhibited in the presence trace amounts of BHA and the inhibition time was found to be proportional to the concentration of BHA over the range 1.00×10 −7 –1.20×10 −4 mol/L. Two calibration curves were obtained: the first linear regression is over the range of 1.00×10 −7 –2.00×10 −6 mol/L, and the second linear regression is over the range between 2.00×10 −6 and 1.20×10 −4 mol/L, with a lowest limit of detection of 4.00×10 −8 mol/L. UV spectra measurements were employed to clarify the possible perturbation mechanism caused by BHA on the B-R oscillating reaction.
研究领域:
分析化学
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化学动力学
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DOI
高影响因子
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