Pyrogallol(pyrogallic acid)is easy to be autooxidized,forming a free radical under alkaline condition,but the mechanism has not been clear.The mechanism of the autooxidation of pyrogallol was studied with ESR,UV and N...Pyrogallol(pyrogallic acid)is easy to be autooxidized,forming a free radical under alkaline condition,but the mechanism has not been clear.The mechanism of the autooxidation of pyrogallol was studied with ESR,UV and NMR techniques and it was found that pyrogallol was autooxidized to a quinone radical under alkaline condition.And at the same time oxygen recieved an electron from the reaction to form superoxide anions,the hydroxyl free radical was then produced by HaberWeiss reaction.The oxygen free radicals generated from this process promoted the autooxidation of pyrogallol.展开更多
Isoproterenol (ISPR) is an important catecholamine‐based drug that is widely used in the treatment of heart disease. However, overdose of this drug is very dangerous to the human body. In this study, a new sensor b...Isoproterenol (ISPR) is an important catecholamine‐based drug that is widely used in the treatment of heart disease. However, overdose of this drug is very dangerous to the human body. In this study, a new sensor based on a pyrogallol red modified‐multiwalled carbon nanotube paste electrode (PGRMMWCNTPE) was prepared and used for high sensitivity determination of ISPR in aqueous solution. Electrocatalytic oxidation of ISPR at the PGRMMWCNTPE was investigated by chronoam‐perometry, cyclic voltammetry, and square‐wave voltammetry. The values of the catalytic rate con‐stant, electron transfer coefficient, and diffusion coefficient for ISPR oxidation were then calculated using voltammetric data. A linear calibration curve was constructed for ISPR concentration in the range 0.8–570μmol/L with a detection limit of 0.47μmol/L ISPR. The sensor was then applied to the determination of ISPR in urine and drug samples with satisfactory results.展开更多
The interactions of pyrogallol red (PR) with proteins and a derivative method for the determination of proteins were proposed. In the pH range 2 56-4 10, PR interacts with proteins, including bovine serum albumin, hu...The interactions of pyrogallol red (PR) with proteins and a derivative method for the determination of proteins were proposed. In the pH range 2 56-4 10, PR interacts with proteins, including bovine serum albumin, human serum albumin, lysozyme, chymotrypsin, resulting in enhanced resonance light scattering(RLS) with the maximal peak at 360 0 nm. With the enhanced RLS, proteins in the range 0-5 0(μg/mL can be determined with the determination limits between 10 3 and 32 2 ng/mL depending on different protein. The effects of foreign substances were tested. The method has been applied to the determination of protein in the synthetic samples and human urine with satisfaction results.展开更多
The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and...The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and superoxide anion free radical(O 2 ·- )of the extracts of seabuckthorn root bark,branch bark and leaves were measured through Fenton reaction and pyrogallol autoxidation method.The results showed that the seabuckthorn root bark,branch bark and leaves had a strong capacity on scavenging free radical.The scavenging rates of hydroxyl free radical were 69.2%,62.2% and 74.1%,respectively.The inhibition rates of superoxide anion free radical were 10.5%,12.3% and 33.3%,respectively.Finally the antioxidant mechanism of seabuckthorn flavones were tentatively explored.展开更多
文摘Pyrogallol(pyrogallic acid)is easy to be autooxidized,forming a free radical under alkaline condition,but the mechanism has not been clear.The mechanism of the autooxidation of pyrogallol was studied with ESR,UV and NMR techniques and it was found that pyrogallol was autooxidized to a quinone radical under alkaline condition.And at the same time oxygen recieved an electron from the reaction to form superoxide anions,the hydroxyl free radical was then produced by HaberWeiss reaction.The oxygen free radicals generated from this process promoted the autooxidation of pyrogallol.
基金Majlesi Branch, Islamic Azad University, for their support
文摘Isoproterenol (ISPR) is an important catecholamine‐based drug that is widely used in the treatment of heart disease. However, overdose of this drug is very dangerous to the human body. In this study, a new sensor based on a pyrogallol red modified‐multiwalled carbon nanotube paste electrode (PGRMMWCNTPE) was prepared and used for high sensitivity determination of ISPR in aqueous solution. Electrocatalytic oxidation of ISPR at the PGRMMWCNTPE was investigated by chronoam‐perometry, cyclic voltammetry, and square‐wave voltammetry. The values of the catalytic rate con‐stant, electron transfer coefficient, and diffusion coefficient for ISPR oxidation were then calculated using voltammetric data. A linear calibration curve was constructed for ISPR concentration in the range 0.8–570μmol/L with a detection limit of 0.47μmol/L ISPR. The sensor was then applied to the determination of ISPR in urine and drug samples with satisfactory results.
文摘The interactions of pyrogallol red (PR) with proteins and a derivative method for the determination of proteins were proposed. In the pH range 2 56-4 10, PR interacts with proteins, including bovine serum albumin, human serum albumin, lysozyme, chymotrypsin, resulting in enhanced resonance light scattering(RLS) with the maximal peak at 360 0 nm. With the enhanced RLS, proteins in the range 0-5 0(μg/mL can be determined with the determination limits between 10 3 and 32 2 ng/mL depending on different protein. The effects of foreign substances were tested. The method has been applied to the determination of protein in the synthetic samples and human urine with satisfaction results.
文摘The content of flavones of the seabuckthorn ( Hippophae rhamnoides L. )root bark,branch bark and leaves were determined using UV vis spectrophotometry.In the meantime,the scavenging hydroxyl free radical(OH ·)and superoxide anion free radical(O 2 ·- )of the extracts of seabuckthorn root bark,branch bark and leaves were measured through Fenton reaction and pyrogallol autoxidation method.The results showed that the seabuckthorn root bark,branch bark and leaves had a strong capacity on scavenging free radical.The scavenging rates of hydroxyl free radical were 69.2%,62.2% and 74.1%,respectively.The inhibition rates of superoxide anion free radical were 10.5%,12.3% and 33.3%,respectively.Finally the antioxidant mechanism of seabuckthorn flavones were tentatively explored.